Your comment about Photography editing tools caught my attention. Photography is a large hobby for me too.
Like Eddie says your motherboard has plenty of PCI slots to work with. 750 watts should run any card you choose. I am NO Expert. I do recall that DirectX v12 support was also critical in the spec but that may have been specific to something I am using.

I notice the same trend in video card demands, more more more! with each release. I am an Adobe LR & PS user. This demand for CPU, RAM and GPU are what moved me to a larger system as well. I notice the speed delivered by the GPU. I think that a Solid State system drive has become a good investment. (Cost++Performance When you are ready)

This trend is very likely to persist into the future with larger image files, Stacking, AI and at the same time CPU power increments tapering(contradicting Moore Law).
{stating obvious} for Graphic processor bigger is better and will carry you further into the future.

I have been very pleased with ASUS NVidia GeForce cards. Like Steve suggests older versions could hit your sweet spot of Cost++Performance.

cheers Roy