[opan]

In sway, put the lower priority windows in another workspace, or the scratchpad, or in tabs/stacks. You can bind keys to focus specific programs by their appid/class also, so even if they're on another workspace or monitor it'll jump right there.

It sounds like the scratchpad may be especially close to what you want.

[hombre_fatal]

Your sway solutions are hacks around the MRU stack of a stacking desktop environment though.

I don't want to leave the workspace nor go find which tab/stack I've put Spotify just to use it. And scratchpad is no better since I'd have to do an explicit summon/dismiss cycle between workspace and scratchpad just to recreate behavior I already have on a normal desktop env.