I could have word for word written almost exactly this blog post, that's how dead-on-accurate I find it, and how similar OP and I's experiences are (down to when and why we originally switched to Sway - mixed DPI long before Wayland was really "stable" for a daily driver).
Niri is incredible, and has completely eliminated the mildly infuriating bin-packing and layout-optimization problems that TWMs exhibit, without sending me back to the floating WM dark ages. I wish Niri had existed like 10 years ago, but I'll accept it existing now as plenty good enough.
I could also say the same, including the Wayland origin story. I'm pretty new to Niri — I only started playing with it about a month ago — but it's just absolutely that little bit more than Sway I didn't know I needed.
Niri is incredible, and has completely eliminated the mildly infuriating bin-packing and layout-optimization problems that TWMs exhibit, without sending me back to the floating WM dark ages. I wish Niri had existed like 10 years ago, but I'll accept it existing now as plenty good enough.