I don't think there would be any guarantees, as it is a free product. So, it would be based on things like the availability of patches upstream (kernel.org), and how many people need the fix, as well as how much effort you are contributing to the fix (be it testing, willing to replicate the issue, etc...)

So to be certain, using these drivers in subsequent releases should be done with caution.

Are there any plans to add testing for these specific drivers/hardware?

If people donate hardware - probably yes. If people with such hardware would be willing to run tests, then probably yes. Otherwise - my guess would be no, no specific testing for such drivers would be made.

It's worth noting that the drivers are still in the mainline Linux kernel and many other distros. If they have a problem it's not just Alma vs the world to figure out the issues - it will be Alma plus the world working on the solution.