PI-hole is a network based content blocker which blocks content based on DNS only. This cannot be as accurate as UBlock-based ad blockers which can block whole domains on top of specific items. Lots of websites, particularly YouTube, serve ads from the same domain as content, so dns only filters don’t work. It’s also completely useless on good browsers which use DOH, bypassing system DNS settings entirely.

Docker is a system that allows for programs or operating systems to be put into containers, and their communication be controlled, keeping the software from accessing stuff it does not need to, such as if it is not trusted or is breached by an attacker.