Unfortunately, Microcenter’s selection often leaves me disappointed. In particular, they stock almost no ECC RAM for AM5 machines. They do not stock many graphics cards that have ECC VRAM either. Their best card in stock that has ECC VRAM is this nearly obsolete ampere card:
I get it, but as "professional" grade equipment, most customers would acquire that through their employers' vendors.
It also depends on your local market; my location seems to carry more server and HEDT gear than others (they stock more A- and W-series GPUs than 5090s, at least). They've also purchased things I've requested, like ECC DRAM for my Threadripper, which I also purchased from them.
I wouldn't be surprised, most retailers can place special orders for things they don't have in stock. I do this at my local record store, book store, and comic store with some frequency.
https://www.microcenter.com/product/652517/pny-nvidia-rtx-a4...