Coreboot is the solution here, but it's just a shame so many hardware manufactures are so protective over their shitty firmware.

Why can't they just open-source whatever they crapped out, and have professional developers maintain it for them for free?

Startup finished in 2.680s (firmware) + 826ms (loader) + 2.977s (kernel) + 12.269s (userspace) = 18.753s

I had to enter my password 3 times to login, that's most of time spent here :) (8 to 10 seconds to the login banner).

I think you have an Intel machine. For some reason, Intel machines spend large amounts of time initializing their firmware. Xeon servers spend minutes at it, while Epyc ones spends only ten seconds or so. But even Intel laptops seems slower than Ryzen ones for some reason.

Edit : I had an update and rebooted (password entered once this time :)

Startup finished in 2.557s (firmware) + 799ms (loader) + 2.901s (kernel) + 5.103s (userspace) = 11.362s graphical.target reached after 5.093s in userspace

Login banner appeared a little less than 8s after boot.

Mine machine only shows kernel + userspace. Even that alone adds up to 15.648 seconds.