If you are logging in in multiple *nix systems I suggest you keep the Ctrl+l.
I started to notice that the more I adopt in terminal specific commands to MacOS the hard is to be productive while I login to various systems.
I want also to force myself (but did not do it yet) to use a simpler Vim configuration. Maybe just line numbers so that when I login into a new system I should not need any plugin or any other shortcuts. Still I like my .vimrc file but I plan to do this in near future.
I assume you're talking about physically logging into different machines since cmd-k is a shortcut key for the terminal and will work regardless of which machine you ssh into.
cmd-k works well for me since I don't think I've personally logged in directly to a non-Mac *nix-like system in 15+ years.
vim is different since it requires configuration on the same system.
Of course it only clears when you run a new command, or press enter. Basically think of it like typing clear after running a command. You can also scroll up and find the last output.
I guess that's my goto.