The linux laptop they propose comes by default with an included Pro license, home edition would need to be selected extra. I haven‘t used Dell in a while, but I‘d assume that it behave like Lenovo and has the License Key baked right into the EFI, so there‘s literally no need to deal with any upgrade license if you proscribe which Laptop Model people are allowed to purchase (which they do)

They also mention multiple times that Linux and MacOS are free, as opposed to Windows Pro - which can reasonably be read as „we don’t want to spend money here“, since otherwise you could just strike these arguments and revert to „we don‘t believe Windows Pro is secure“, which incidentally they never say.

They specifically mention Dell laptops with Ubuntu preinstalled.

If you follow the link to the model in their page, it selects the default version with Windows 11 PRO. You can explicitly choose Ubuntu, but it‘s not the default. My point here is „acquiring the license for a windows based laptop is a non-issue if you‘re willing to spend the 70USD it costs.“.

The problem is generally less the individual pro license and the associated enterprise licensing costs that come with managing said device in Azure AD/InTune.

Any laptop above the absolute bottom tier can be purchased with a pre-installed Windows Professional license. It's a complete non-issue.