You might want to read this thread: Choosing a GPU for DxO Photolab: the answer?
The gist of it is that a French tech site (or magazine?) used PL8 as test software to test GPU cards - and Noir Foncé put their results into a table showing price/performance. The AMD Radeon RX 9070 outperformed the RX 5080 and the RX4090 for a lot less money.
I used that advice when building a PC, used an AMD Ryzen 7 9700X, that RX 9070 (w 16G DDR6), 32G system memory and PCI5 SSDs and using PL8 it takes about 2.5 seconds to export JPEGs from my Nikon D850 (similar resolution to your camera). I haven’t moved to PL9, will probably get 10 when it comes out.
As a side note, I got a BeQuiet case and AIO. I was concerned about noise, the case came with optional high airflow panels. I tried those and the PC is very quiet in what’s now a high-airflow case.