According to Wikipedia, A028 is an open/free version of Albertus and widely available on Linux.

You could also download versions of Albertus itself to use in KDE - there seem to be lots of versions.

Fonts are easy to install in KDE, if what you want is not in your package manager then download the font files and install it with the Font manager tool in Settings (just look for Fonts). You can install fonts from files you have downloaded or download more from the KDE store (I don’t know if A028 is in the store).

It’ll be available immediately in LibreOffice, and you can also use Konsole settings to use the font for your terminal.

If you want to pay for or pirate a font, there’s of course Albertus. The best free (OFL) font I’ve found with a similar look is Della Respira, only a single-style font:

I’m not sure how you plan on using a proportional font in the terminal, though.

You can have Albertus, there are several digitalizations, and some clones like Flareserif 821.

Check out the font A028, which should be free and come in a couple of different weights.