That should run pretty decently for 1080p editing in FCP. Probably not the best for heavier and/or higher than 1080p workloads though.
It is a good all-round GPU for the 5,1 though. The Navi cards that came after it (RX 5000/6000) can run in a 5,1 (even the top-end 6900 XT), however Ventura stopped these cards from working as the drivers need the AVX2 instruction set to function, which the CPU's on the 5,1 (and also the 6,1/2013) physically do not support.
So the only Mac that the RX 5000/6000 cards can work in with Ventura or later is the 7,1 Mac Pro, along with any Haswell+ based Macs which can support an eGPU.