Depends, assuming your card is new enough (RX460 or newer). It should has a working UEFI GOP onboard, which allow you to use RefindPlus, or the OpenCore boot picker.Any possiblity of using eEFIind Boot manager (or equivalent) safely with Open Source Legacy to get back boot option
P.S. The card must not be flashed, any modification to the VBIOS (e.g. undervolt for mining, this often happen on used cards) will disble the GOP. And you have to flash the original factory ROM back in to re-gain the boot screen ability