If you go to this site there a few free networking courses:
academy.ripe.net/
To those who don’t know RIPE are responsible for handing out IP addresses to orgs in Europe and some of the middle east too!
They have very high quality courses for free. The exams you get for free if your organisation is a member…. however if you look out on mastodon they give out exam vouchers in the summer if you complete one of their courses
https://mastodon.social/@ripencc
They are a very friendly bunch!