Something I realized after spending a few months in sway (i3) and then niri is that I only care about a few windows (code editor, terminal, browser, apps I use moment to moment).
All the rest I'd prefer to just summon as-needed and then dismiss without navigating away from the windows I care about.
sway/niri want me to tile every window into some top-level spot.
Took me a while to admit it, but the usual Windows/macOS/DE "stacking" method is what I want + a few hotkeys to arrange the few windows I care about.
Yeah, I came to the same conclusion a few months back. Sadly I had to ditch KDE for GNOME due to an issue[0] specific to NixOS but after going through the gauntlet of tiling window managers and PaperWM/Niri over the years I've also settled on a traditional DE.
I'm surprised to hear that niri didn't work for you, I feel like it's a really good middle ground between tiling and floating window managers. It handles a lot of window resizing and arranging for me, without being too rigid. Windows can have any width they need without having to evenly divide my monitor.
Makes sense I guess. I mostly work with a few long-lived applications, and I hate having to do any manual window management myself.
I'm fairly sure you could use scripting to come up with a Niri workflow that worked for your use case. Maybe something like niri-scratchpad (https://github.com/Vizkid04/niri-scratchpad). But I sympathize if you don't want to spend a ton of time experimenting with your tools when you already have something that works for you.
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.
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.
All the rest I'd prefer to just summon as-needed and then dismiss without navigating away from the windows I care about.
sway/niri want me to tile every window into some top-level spot.
Took me a while to admit it, but the usual Windows/macOS/DE "stacking" method is what I want + a few hotkeys to arrange the few windows I care about.