I was a tiling user for quite a while.similar setup to you (used awesome then qtile, short stind with xmonad and ended up with i3 and then switching to Wayland with sway, but tried hyprland for a bit as well). One thing I always ran into was that I generally found that more than three windows are horizontally just doesn't work and vertical splits very often make windows to small either. On the other hand I would often find that I wanted a new window next to something I was reading or working on, or e.g. I'd have some terminals open and wanting to plot from ipython. That always caused quite a bit of friction, i.e. I'd have to either collect some windows into a stacked layout before opening the new window. Or moving some of the windows is want side by side to a new workspace. That for me meant I had to think about what I was doing when window managing, taking my focus away from my actual task.

With niri I just open another window and it's where I need it and all other windows are still to the left and right so I just "scroll" there. Now I'd say my workflow is messier now, but I think that's actually a good thing. Tiling window managers require (but also make it reasonably easy) to be organised. With niri I don't have to be organised. Sometimes it you can't find a window immediately, but you can just use overview (and I also have a window search rofi). Initially I still had some named workspaces similar to my sway tags, mainly because I found I was still switching to them out of habit. Nowadays I don't use them any longer.