Javascript at scale combined with teams that have to move fast and ship features is a recipe for this.
At least it's not Atlassian.
You might be thinking of Fisheye/Crucible, which were acquisitions, and suffered the traditional fate of being sidelined.
(You are 100% correct that Stash/Bitbucket Server has also been sidelined, but that has everything to do with their cloud SaaS model generating more revenue than selling self-hosted licenses. The last time I used it circa 2024, it was still way faster than Bitbucket Cloud though.)
Source: worked at Atlassian for a long time but left a few years ago.
I use it every day and don't have any issues with the review system, but to me it's very similar to github. If anything, I miss being able to suggest changes and have people click a button to integrate them as commits.
So I'm back to liking dev-ops and github code reviews identically!
Shockingly, the best code review tool I've ever used was Azure DevOps.