My favorite way to use Mastodon. The share feature that resolves the fediverse links is so handy (the small option on the right of the popup after sharing to Moshidon). The official app’s only share option is to post the link, which I would not be doing 99% of the time.

Settings > Battery and Device Care > Battery > Background Usage Limits > Never Sleeping

Add all the apps you want constantly running to this list.

There’s no need to go JavaScript route for theming, Stylus is an add-on that injects CSS instead. I wrote a style here, which increases width of Lemmy instances for wide screens, and also respects your browser light or dark theme if set to follow system:
https://userstyles.world/style/10233/zettajon-1440p-and-darkmode-supported-lemmy