Contestant computers boot a Linux image that contains all the interpreters/compilers and documentation for the supported languages, some editors/IDEs(vim, Jetbrains, Eclipse, etc) and a web browser.
Network access is limited to the judging system only.
My experience in Europe is that most universities can support this.
This is basically how ICPC works (https://icpc.global/)
Contestant computers boot a Linux image that contains all the interpreters/compilers and documentation for the supported languages, some editors/IDEs(vim, Jetbrains, Eclipse, etc) and a web browser.
Network access is limited to the judging system only.
My experience in Europe is that most universities can support this.