Reinstall Ubuntu on XPS 9315

I notice that the pre-installed Ubuntu 20.04 is installed on an unencrypted volume. Unfortunately, this means I cannot realistically use it for work. As volume encryption cannot be performed retrospectively, as I need to reinstall Linux on a volume that is encrypted (LUKS). I've done this on other machines, but using the Ubuntu vanilla installers. I note that this Laptop has a version of Ubuntu that is configured specially to be certified (and it works really well).

I the Dell rescue ISO allow me to do this?

Better - are there instructions on how to set up Ubuntu 20.04 to the same state as a factory machine? This way, I would maybe use Kubuntu, Mint or another Ubuntnu 20.04 derivative.