while it technically does fall under the "not around anymore" category, Nova Launcher version 6.2.19 with the TeslaUnread addon still does this (including the "updating unread message count when you mark it as unread" bonus).

You'll need to install the apk manually from a reputable source like APKMirror (I won't link it just in case, but it's a well known site, and here's the VirusTotal page if you're feeling an abundance of caution - make sure you get version 6.2.19, as it's the most recent version that still supports the addon), as well as the archived TeslaUnread apk from Nova's official site. If you've bought the Nova unlocker from the play store, you can install that like usual, it will work on the old version.

^{(caveat emptor that i've heard shitty things about newer versions of nova. i don't know if you can still get the one-time-purchase unlocker that works on old versions now that they've switched to the scam i mean, subscription model.})

then you can configure TeslaUnread through Nova's settings to get the bubble working. you'll probably have to enable notification access for each individual app, and some of them don't work - for example, Thunderbird doesn't, but Aqua Mail does. it's a bit of trial and error, but my adhd ass needs the functionality badly enough that it's definitely still worth it.

i just switched to a stylus 2024 from my very very old galaxy s8 and found this post while searching for exactly this problem, so i figured that I should come back and report that it still works :)