You can have a look at the recommended GPUs in DeepPRIME* hardware acceleration – Customer Support
Ultimately it is a choice between the price of the GPU you’ll use, the hardware compatibility with your current PC and the final export time. Fastest GPUs obviously cost more and may need more power than your power supply unit may be able to provide.
The spreadsheet linked in PL4 GPU benchmarking? - #21 by jch2103 gives good hints about this by comparing the times for different hardware setups.