There are plenty of video courses, stuff on Udemy teaching you databases, etc.
I think it's an untapped market for the webbased coding challenges, although quite hard to pull off if you are needing to have a database for the users to interact with, etc. The same would apply for any network-based challenge, or ones requiring interacting with an API, etc.
If you've ever played with HackTheBox / TryHackMe (hacking playground) they provide VPN config details where you connect and can access all sorts of services, DBs etc to hack.
I imagine a similar solution could work for coding, networking etc training.
I think it's an untapped market for the webbased coding challenges, although quite hard to pull off if you are needing to have a database for the users to interact with, etc. The same would apply for any network-based challenge, or ones requiring interacting with an API, etc.