> Alacritty I like but the lack of tabs is not acceptable for the moment... and before you ask: I hate tmux. So much more key presses to achieve basic functionality, it boggles my mind why people love it. But, to each their own obviously.

Tabs usually mean mouse+click to switch which takes way more effort that a simple alt+number or similar keybinding used to switch "tabs" in tmux. I'd guess that some terminal emulator tabs allow keybindings to switch tabs as well but, modelling OP, I'm focusing on the expected default experience.

No, zero mouse usage, you can both address each tab by number and just moving between them. I wouldn't have any terminal emulator without the latter feature at least, and all I've tried support it.

I hate mixed mouse + keyboard workflows as well.