There's no lock-in in MacOS, which is easily demonstrated on any front you like. Of course, if you actually investigate such claims before making them, it'll put you in the awkward position of having to decide if you'd rather be ignorantly disingenuous our outright dishonest, so it's a tough spot for you.
Also, Asahi is a very polished distro with a lot of original work going into it, arguably one of the best Linux experiences around, so I have no idea what you mean by "no chance of switching".
You are no more and no less locked into MacOS than you are under Windows or under Linux.
I'm not sympathetic to them, but there definitely ARE substantive arguments a FOSS devotee could make about MacOS that make sense, or which are at least grounded in fact. This is not one of them.
The hardware bring up they have done is amazing work, but it's a long way from daily driving. It's not the developers' fault apple uses bizarre webcams etc, but "best Linux experience" is not even close.
That said, Lenovo and the thinkpad brand are known bad actors. They were busted for phoning home and adding spyware. Not trustworthy.
Fresh install of Ubuntu or Fedora that formats the HDD should rid you of anything dubious.
You can patch out WUBT by replacing your bootloader with one that strips them out, though most boards have a toggle in the BIOS by now (my ASUS AM5 board had this anti-feature and the toggle too). Though you probably get more crapware on Windows Update these days.
I agree about lenovo as a whole, but IIRC that spyware was never on the thinkpad brand, only ideapads and other lower end machines.