I have a question: will I have problems installing Nix or Haskell on an Ubuntu VirtualMachine over Win11? Will I have problems with Plutus in the future? Would it be better to install Ubuntu only on one PC? Thank you.
Installing the required toolset in an Ubuntu VM is perfectly fine and quite documented. In fact, it is the method used by many, as it isolates the environment from the host avoiding problems in certain cases. You can check this recent thread for more details:
Be aware that in any case, your Win11 host, a vm on it, a cloud vm, or even another computer, will need a minimum of 8GB of free RAM and around 35GB of free disk space dedicated to the environment.