Apps leaking memory in Android are just going to get automatically get killed by the OOM killer, I don't think a restart is going to address that particular concern.
I have an S7 (yes I know it's old) I still like it and it works - but - something happens about once or twice a month and it starts hanging up whenever a phone call connects and/or an app will get super laggy.
Anyway, reboot fixes it (so far) and nothing else I've tried does.
There's definitely something with these older phones that is like a slow leak and the simple, easy, lasts for weeks fix is to just take 2 minutes for a full "turn it off and back on again"
Plus the overheating when something gets stuck doing a background thing. Reboot reboot.
I plan to use this phone until it dies, reboot stops fixing things, or needed apps are no longer working/supported.
Slack no longer works/supported, but that one I'm just like "oh, noooo"
However I expect ones I actually need to start falling off and I'll be lucky to get a couple more years of use.
My meandering point, some of us are still using Android phones where reboot helps a lot
Especially since Most Android Apps are written in memory Safe languages Like Java or kotlin.
It is most likely Apps getting stuck doing a Background process indefinitely
It's not out of the question to have 'memory leaks' - apps accumulating more memory by keeping around references to more and more objects - but memory leaks in the stricter sense of not deallocating objects that you no longer have references to is less likely. Regardless, the OOM killer will come for your app, no matter how good you've been about managing your memory, as long as someone else wants to have the memory and you're the one who has been active the least recently.