for_window [all] floating enable
I use the multiple desktops feature a lot, though. Some programs are pinned to a dedicated desktop and run all day. Others I start in (or move to, later) a numbered desktop, and switch to them by changing the desktop. Often, most of the desktops contain only one window.
I once used i3 and sway the right way, of course. I guess I had one too many of those programs that were not designed to work at arbitrary window sizes, added the above rule and called it a day.