@th do you have both 12 and 13 installed? if so, it’s easy to do. i did it from 13 to 15 the other day.

the steps, in summary: https://www.paulox.net/2022/04/28/upgrading-postgresql-from-version-13-to-14-on-ubuntu-22-04-jammy-jellyfish/

there are lots of blog posts (blogspam?) listing the same steps.