Sorry to not really answer your question, but I’m just curious what distros and kernel combinations you’ve tried on your 2020 thinkpad that don’t support the hardware keys? I never ran Linux on a thinkpad but I’ve heard that they are fairly well supported. Also, I wonder if it’s an issue with you desktop environment, which ones have you tried? I’ve seen most hardware features seem to work on KDE but many didn’t on xfce for example.As a bit of an anti-consumer, I would recommend trying a few totally different distros and DEs with the latest kernels just to be sure that it’s really not supported.

To answer your question a bit. I’ve honestly not had issues with drivers of any kind on any desktop hardware since I started using arch with KDE. I don’t even bother checking compatibility anymore. This is even true for Nvidia GPUs although there are some issue with Wayland there. For a laptop, I do watch videos of people opening them up to fix or upgrade them before I buy. If the laptop is hard to open or upgrade or if it breaks easily during the process because its only held together with plastic clips and glue then I don’t suggest you buy it unless portability is more important to you than device lifetime.