I was an i3 and away user before switching to Niri.

I generally use one workspace per task with some workspaces dedicated to specific apps (eg my browser workspace). Every app is full screen, always. I tend to use niri’s scrolling mainly for related work on one task, for example, I have my editor working on a project, scroll left and I have kilo code open on that project, and scroll right I have terminals or other related things.

So I mainly use a sway-like workflow except things tightly coupled to a specific task as on the same workspace and I scroll left or right to get to them. Everything is either full screen or sometimes 3/4 width (and full height). Occasionally I have two terminals vertically split on one column.