...once
I would be so worried about destroying the GPU I'd sooner remove the motherboard and reinstall them both as a single component. Idk if it's just me but I always have an ass of a time getting the GPU in and out of the PCI slot with some trepidatious combination of rocking, pulling/pushing what feels like way too hard, and destroying my fingers trying to operate that little slot lock piece. Skill issue?
Is there any way to support you outside of attempting this in parallel for ideas/breakthroughs?