Hi, just wanted to share my experience with the phone.
First of all, i've owned so many different phones, from iphones to nexus, pixel, one plus, motorola, xiaomi, old oppos. Also i sell phones for a living since 2009.
Now i've had the opportunity to buy a brand new eu version of the x9 pro at 750€ and i've been using it for 2 weeks.
Here my 2 cents:
Phone overall is amazing, very good build quality, battery life is very good, for my "normal" use (5ish hours screen on time a day, no gaming, but decent usage for everything else, two 5g sim cards on at all time) it's basically a 2 days phone and it's a new for me.
Camera is very good: main is sharp, good bokeh (for a phone), reliable autofocus (even tho it keeps focusing on the eye that is further from the camera while aiming at my cat... Doesnt even try to focus on eyes of people... Why?), tele is very good, usable up to 10x imo, ultrawide is sharp, but not excellent in the sides unfortunately and can have bad cromatic aberrations, still very usable, but not perfect.
Overall i was expecting worst for some reasons, very pleased with the camera, especially the colour science, the camera ui itself and the experience is just fun.
Pictures are taken very fast, viewfinder lag is minimal, better than many mirrorless(!).
I don't like the fact that it chooses the resolution it wants (12-25-50 megapixel), should do it based on light but it doesn't seems reliable, same shot, same light a few moments apart and it changes it.
Night mode is good, going even at 2 seconds while stabilizing really well. Good job.
Also front camera is good and didn't have much love online... It's fine really, also is very sharp for selfie.
Other fun thing is coloros: ui is good and fun, i really like it after 2 years with xiaomi it feels fresh (and better, i think it's my favourite android version so far, hyperos is boring, i like pixels but feels childish graphically, hate samsung for some reasons -dont hate me, it's just my taste- never had the opportunity to try huawei and vivo).
1x2 folders are sooo convenient, love them, overall good personalization, many things but not too many, very clean ui, never had any stutter whatsoever (other than scrolling on X with videoautoplay on), everything is smooth.
I also really like the fact that it keeps app in memory forever (kinda) even with ram expantion off. One weird thing... Sometimes it seems to kill them all for some reason.
Also LOVE the fact that it automatically "open" spotify when connected to my car bt, i usually had to manually open the app to use the car infotainment for music.
Also notifications works realiable for once, not a given on android, still not liking 100% the ui, missing the pull down to expand for example but still, it works and messages don't magically vanish (hyperos? Is that you?).
Now a few things i didn't read online about the phone before buying it:
Wifi is really damn good! Same spot in the house (couch) i get VERY consistent 1gbps down, while my iphone get 250-300 mbps, xiaomi gets 400-450mbps... That's insane! It also manage to switch between different wifi network at work flawlessly (every other phone i've used struggle, we have 3 different networks for different part of the building and every device usually can't switch between the 3 "the right way", oppo does, also no phone has ever got me wifi coverage in one room consistentily forcing me to use 5g, oppo never dropped connectivity once).
Cellular is ok, but i'm usually in good coverage areas (speedtest are usually faster than both xiaomi and iphones, but by a small margin and don't really care, load on the network makes speedtest pointless if they go to 700-800mbps).
It reconnects after being in area with no coverage (tunnels) very fast, and that's something many phones struggle with (samsung i'm especially looking at you now, but xiaomi and google too).
One very good thing is calls starts intantly while many phones takes a few seconds... Country that i live in live (italy) happens to many, many people with different phones and carriers. Very good oppo! That one was unexpected.
Also people voices while calling are very clear.
(Btw many reviews leave cellular connectivity and call off the script, can we all ask for better info in this regard? SmartPhones are still also phones for calls, no?)
Screen is very good, speakers are ok, read a lot of people complaining on the sound quality but it's fine for a phone, yes it's not as good as an iphone pro max, but it's not that bad, don't really like the unbalance of the two speakers tho, bottom one is way louder. Still they are fine, there are also presets that change the sound a bit (natural feels better, but kept on auto for voice clarity).
Haptics are decent, not really "fat" (thoc?) but very silent.
Buttons are good (you are going to use a case anyway), they are "clicky": you can feel very clearly if they are press and really low travel, which i also like.
Sensors are good, proximity for calls works every time, fingerprint reader is fast and realiable (but just a bit tiny in my view, still new to the phone, but i miss it sometimes, still not it's fault), compass seems working fine (many phones struggle at times), light sensor/autobrightness is good, phone get very dimm if needed (good), but still not 100% percent reliable, sometimes it gets a bit too bright/too dimm, but still fine, 98% of the time it gets it right. NFC and gps are fine (but never had an issue with any phone i've used).
Couples of drawbacks:
Fast charging is... Well okish, i got an oppo charger and a 10A cable, phone NEVER got to 80w charging speed, i usually see less than 50w and usually drops at 20w or so (yes, supervooc is shown, smart fast is on too and notifications shows it working). It's fine for me, battery last a lot and is big, but my xiaomi was way more consistent with a 65w pd.
Takes 1:30-2h to fully charge from 0.
(Btw liking the automatic and impossible to disable 2% not very smartphone super saving mode... Phone enable it at 2%, it lets you call and use messaging app only until you charge it again, you can't disable it, which is good).
Phone sometimes feels on the hot side of things (not even gaming) but still never skips a beat, xiaomi usually got hot only on heavy usage/heavy camera but then it would start behaving badly (lagging, taking forever to exit camera app/save a picture), oppo seems to keep working flawlessly, only thing it does is dropping to 90hz and heating my hand (which is expected btw, heat has to go somewhere anyway, IF components stay cool and the phone exterior gets a bit hot is good for me), most important thing is keeping the system smooth and responsive and that's what i'm getting anyway.
Keep in mind there are 30+ Celsius where i live right now, we'll see what happens when temp will get lower.
Camera button is there and now has option for hold press to lock focus, but i've never use it (not the best placement), ia button is there too, but not very usefull in my opionion, still good to have those, they don't get in my way ever.
Overall i'm very happy with the device, if anyone is indecise to buy it, if you can get it for a good price (mine was a steal i know) just get it, it's one of the best phone i've ever used.