Problem is if I see a note on my feed from AccountA, I want to boost it from AccountB, but not follow that profile. It's likely more than 10 clicks to accomplish that, then more clicks to navigate back to your starting point. Some folks would just forego the boost & move on, which is very suboptimal.
Making such a thing easy would be suboptimal for me because of my reasons for having a separate account. That's my point. A good middle-ground would be to just have account switcher settings. I say 'just' without understanding the complexity of doing such a thing.
Fork the project & start ripping things out if you don't want them. The account switcher at the bottom works. But I'm genuinely curious what the reason for your sepwrate accounts is, that a new long press toggle would somehow inhibit your experience 🤔
So that is a problem for you but the whole point for me. I can see something like a long press that has a popup for which account you want to boost for or whatever, but I'd prefer to have that as an option that can be disabled.