I used to use Boost all the time, and browsed the site when I was on my computer. Now that I can't access it from my phone (the first party app isn't happening lmao) I don't feel much like using it on desktop either. Tumblr, of all things, has absorbed much of my traffic, and I've paid to remove ads on it because I've used it so much over the last ten years that I know it'll be worth it, plus I'm hoping that if enough people pay for it they won't go down the monetization rabbit hole as much as other sites have recently.
Lemmy is okay, but the hot/active post sorting is far worse than Reddit was (I'm still seeing days- old posts even when set to All) and the user base just isn't large enough yet to have a consistent feed of stuff I find interesting. Both of those can easily change over the coming days/weeks of course.
All social media platforms' viability come down to userbase and how fun they are to hang out on, and reddit has absolutely damaged both. It's unclear to me what impact that will have for it long-term, but its time as the problematic but scrappy underdog in the space is over.