After the Salesforce takeover? The one in 2010? So Heroku was good in like a year!?
Then, year by year, those things were taken away. Eventually, circa 2018, investment in the core H product started being reduced and individuals and teams started being reorged to focus on Salesforce priorities. H became a "keeping the lights on" job. Folks who wanted to keep pushing left to work on GitHub actions or on render.com, netlify, other places still striving for great devex.
(guess based only on having watched things unfold from the outside without ever being a user/customer so please do add salt to taste)
1. GitHub integration breach, which wasn't handled well but luckily didn't affect me.
2. No more free-tier DBs :(
3. Salesforce logo, which ofc doesn't matter.
Hearing vague negative things here makes me nervous about the future because I really like Heroku and don't want to be stuck using AWS directly.
I would suggest you start poking around at possible alternatives just in case, but not as yet with any great sense of urgency.
If you Ctrl-F for crunchydata in this comment section you'll find an employee of theirs talking about their postgres hosting and listing a bunch of services their customer use for the other parts of the puzzle, and have hired enough heavyweight core contributors and active and clueful community members that I think it's reasonable to say they're -good- at postgres.
I would say that what I expect to be most likely to happen is gradually increasing prices and gradually degrading service (the people still working on it do seem to care but I don't know if there are enough of them left to avoid bitrot setting in and even if there are today, in a year or two there may not be) so having a plan to move in an orderly fashion but not executing it yet seems like the wise approach.
Neither panicking and moving in a fast and risky way now, nor waiting until (if it happens) things go from aggravating to actively intolerable and moving in a fast and risky way then, are likely to be particularly good ideas.
OTOH, being prepared to migrate elsewhere in an olderly fashion if the cost/benefit calculations tell you it's time, re-running those calculations and double checking your plan every so often, and continuing to enjoy the service in the mean time, seems like a reasonable, responsible, and overall relatively pleasant way forwards.
(disclaimer: I am not a Heroku user myself, but I think the general principles almost certainly apply here just fine, and I'd certainly be comfortable giving the same advice to a consultancy client at work, so without being foolish enough to claim I'm definitely right I'd suggest the above analysis is at least worthy of giving serious consideration to)