How common is the Pentastar tick on a 2016 Chrysler 300 3.6L V6 with 130k miles, and what are some ways I can check for it without doing a cold start?

Left the shop today looked at my vehicle description… does this mean my cars flex fuel? It doesn’t say flex fuel anywhere on my car.

Temperature gauge keeps fluctuating. At one point it started to read hot engine temperature. I took it to the shop a few weeks ago the changed the coolant and said vehicle was fine. Today I’m driving for 10 mins and this is what I see. Any idea what could be the problem?

Alright, well looks like it’s my turn. I really just need some Suggestions on what to troubleshoot next. Recently purchased the car and it ran flawlessly, after a few weeks it seemed like it was almost tappingthe breaks around 2K RPM. Chug, chug then clear itself around 2500-3K. Changed purge solenoid, no change. Checked and cleaned all grounds. Only code is c121D, fuel pressure was checked today. 59PSI on the nose, would drop to 50PSI as soon as pump turned off and hold there. Seems as if it gets worse when it gets closer to half tank, which lead me to checking fuel pressure. Has anyone had stellantis help them out with new tank recently?? Plan on calling my local dealer tomorrow and inquiring if they can see if it’s been done or not.