I'm giving the visual tab-bar a try, by making it less ugly than it is
by default. Hopefully I won't mind it taking up one full row at the top
of the frame.
Packages that need to be loaded on emacs startup, should just be loaded
through use-package in a non-deferred manner.
It makes no real difference to startup, loading the packages either
slows down emacs before "startup" is complete, or right after it
completes. End result is that Emacs is unresponsive for basically the
same amount of time regardless.
Recent native-comp builds glitch out running in a terminal when
tab-bar-mode is enabled and tab-bar-show is set to nil. I'm not sure if
it's a native-comp specific thing, or just latest emacs-28 dev.