As a Thinkpad fan (from Germany, maybe this makes a difference) I have to say that Lenovo usually only let's you buy Laptops without Windows for very crappy machines or if you're a student via Lenovo campus program.
The X13 Gen3 or Gen 4 (both AMD or Intel) are high-end devices. Both allow to ship without operating-system.
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Double checked that. You can also select the OS for the T14s or T14-Intel. The decision of Lenovo for options are sometimes weird. It looks like that ThinkPads preferred for professional usage likely ship without operating-system. Maybe you look for already built-devices only?
Look for the options upon CTOs devices - which makes sense - their built upon request.
Sometimes you can also select Fedora or Ubuntu but I think the majority of Linux user prefer to setup the system itself.
