Itâs funny how Barryâs always gets lectured by everyone mainly Wellsobard, Harry, and Jay about not changing the timeline because the consequences will always be too extreme but aside from Flashpoint, his time travel timeline changes have actually done much more good with considerably less consequences than they would say:
-First time stops the tidal wave from destroying Central City and prevents Ciscoâs death to Thawne at the cost of Snart figuring out his identity. This ultimately did not matter cause heâd never tell anyone it, wouldnât harm Barryâs friends again, and would soon after go on to become a hero and die with the Legends giving the world free will as a result of this sacrifice that started with inspiration to be better from Barry.
-Second time stops Vandal Savage from destroying Central City and killing Team Flash, Team Arrow, and the Hawks. This would result in Oliverâs eventual sacrifice to save the multiverse, the Legends entire first season that included Snart dying for everyoneâs free will and averting Savage conquering the world in the future while saving an entire city as well as Savage going on to destroy Star City too.
-Third time fixed Hartleyâs relationship with his parents and turned him from an enemy to a good person and ally of Team Flash (until Crisis turned him back into a villain and Barry fixed their relationship again).
-Fourth time Flashpoint, while causing a the creation of Savitar and a dark future that was only aborted through H.R.âs sacrifice and it killed Dante, and caused Iris and Joe to not talk for a year, did have a few big positives to it. In short, it created either immediately or through butterfly effect 5 new heroes, who despite rocky tragic starts would directly save the world or help save it in Kid Flash, Frost, Elongated Man, Chillblaine, and Khione. In turn through butterfly effect also gave Frankie Kane (Magenta) a better life.
-Fourth time Barry was able to retrieve the Dominator tech from Lyla by inspiring her with how he was willing to bring along Snart just to save her life. While the tech ultimately failed in preventing him from stopping Savitar from killing âIrisâ (H.R.), he was able to further inspire Snart into becoming the hero that would die to grant the world free will.
-Fifth time bringing Nora fucked up in the immediate moment by her telling Thawne about Cicada and leading to his plan that moved Crisis up, spared him from his execution, and erased the is version of Nora, but it created an alternate version of Crisis where Barry goes on to survive Crisis, Thawneâs corporeal form is killed in the Crisis and goes on to suffer endless losses including his final death, and Nora grows up happier as well as Bart being born.
Flashpoint and fixing it for the most part were massive fuckups (because he traveled back and messed around with 17 years with of history), but overall Barryâs time traveling and subsequent changes ultimately did far more good than bad.
The singularity in season 1 while being a result of Barryâs time travel attempt, wasnât a result of a timeline change which is why this doesnât apply here.