I'm not sure what thread you're referring to (re SEV). A few of us are running Qubes 4.1 alpha on new Thinkpad Ryzen 7 PRO 4750U systems because the older version of Xen used in Qubes 4.0 is incompatible.
The newer Xen in R4.1 alpha still has a bug that affects CPU scheduling, so there is a trick to configuring it for a smooth running system.
Qubes reports that safety features (IOMMU etc) are working. What does not currently work is S3 sleep.
Stability is already quite good if you avoid badly-behaved wifi drivers (unfortunately the Thinkpad's Intel AX200 is in this category, so I use a USB wifi device instead).
I'd say its not too much of a gamble if you're willing to run a new alpha or beta of Qubes. But keep in mind your 4750G motherboard may have significant differences vs Thinkpad laptops; IMO you need to go with a high-quality brand, preferably a pre-built business system from the traditional top-3 (Lenovo, Dell, HP).
Here is a relevant thread: