I'd like to buy a radeon RX6800.

[#1]

I'd like to buy a radeon RX6800.

Has the compatibility test been done for the new product?

I'm using After Effect and Premier Pro.

Will this harm your mental health?

[#2]

That GPU has not yet been tested. However, do not expect much of a performance or quality improvement over the current AMD Radeon GPUs because Adobe has not updated its implementation of OpenCL support since 2017. As a result, performance in Premiere Pro will be slower than with even the cheapest Nvidia RTX GPU. More like the RX 6800 will be no faster in Premiere Pro than a two-year-old RTX 2060.

And with the current available drivers for that GPU, you might have to switch the renderer to the software-only mode (no GPU acceleration whatsoever) in order to prevent problems in the exported video or crashing.