I'm on MacOS. I basically never maximize anything. I just resize the floating windows and put them where they make sense at the time. The dream would be doing this with the keyboard using something like i3. I have been tinkering with that on weekends but M-F I focus on paying work.

Check out Moom. You can save window layouts and replay, save window positions and apply them to any app, arbitrarily move, maximize to a range with a customizable margin, etc etc. https://manytricks.com/moom/

Does anyone know if there is something similar for Linux?

Depending on how exact of a similarity you're looking for, gTile for GNOME/Cinnamon might be of interest to you. I've also found PaperWM to be very productive.

I use gTile for gnome. I had to play around to find a setup that I like. I eventually settled on ignoring most of the features that were offered out of box. Now I have configured a few simple keyboard shortcuts.

For example, Super + Up Arrow will move a window into the central third section of the display. Pressing it again will expand the window a little bit.

Nice and simple. Makes working with large displays pleasant.

I use Rectangle. I’ve configured it with a few keyboard shortcuts that let me move a window into specific regions on the display. I use it to quickly have multiple non-overlapping windows.

I cannot imagine using a large display without it!

BetterTouchTool is _excellent_ for window placement/resizing; also can be triggered externally if you want to combine it with Alfred for Karabiner Elements (though you don't have to, you can define the triggers in BTT itself).