Try some puzzles out here:
https://www.hackthissite.org/

Learn some cryptography here:
https://cryptohack.org/

Practice network stuff here!:
https://overthewire.org/wargames/

Learn about Reverse Engineering here:
https://malwareunicorn.org/#/workshops

Basics of XSS exploitation can be found here.
Check out the testing methods, also the website has tons of web vulns.
https://owasp.org/www-community/attacks/xss/

Or learn a bunch of stuff here:
https://www.hackthebox.com/

You can get certs here:
https://academy.hackthebox.com/

You can learn more stuff here:
https://tryhackme.com/

And finally do bounties here:
https://www.hackerone.com/ - https://www.bugcrowd.com/