You can try https://edubart.github.io/webcm/

WebCM is a serverless terminal that runs a virtual Linux directly in the browser by emulating a RISC-V machine.

It's powered by the Cartesi Machine emulator, which enables deterministic, verifiable and sandboxed execution of RV64GC Linux applications.

It's packaged as a single 24MiB WebAssembly file containing the emulator, the kernel and Alpine Linux operating system.

It comes with Bash, many programming languages (eg. lua, micropython), cli utilities (htop, vim). It has no internet connection.

Disclaimer: I created it.

My old technical school had Immersive Labs, which used remote VMs and had some tutorials around Linux usage.