Stumbled on this while looking for something else. I fought with heavy sag for months before grabbing the Phanteks Vertical GPU Bracket Gen4 for my P500A.

• Phanteks Gen4: Native fit, holds weight well, keeps card far from glass.
• Antec Vertical GPU Bracket PCIe 4.0: Cheaper, but has more flex with heavy cards. My thermals stayed within 2 degrees. Just make sure your riser is Gen4.

Vertical mounts can be risky if the GPU sits too close to your side panel. I suggest looking at the Cooler Master Universal Vertical GPU Holder Kit V3 PCIe 4.0 since it lets you adjust the distance from the glass. The EZDIY-FAB Vertical PCIe 4.0 GPU Mount Multi-Angle is a decent budget alternative too. The Cooler Master kit is sturdier for heavy cards, while the EZDIY is cheaper but feels slightly less secure.

@Reply #2 - good point! Native brackets definitely tend to mitigate some of those stability issues. Honestly tho, seeing your 4080 Super sag reminds me of this absolute nightmare my buddy went through back when the 30-series first dropped. He was obsessed with the technical specs of his riser cable, spent weeks researching signal attenuation and impedance on some obscure LINKUP Ultra PCIe 4.0 X16 Riser Cable. You really have to be careful with those because he was so paranoid about the bend radius and didnt want to lose any bandwidth on his x16 slot. One night we were mid-raid and he starts smelling something like ozone. Turns out his mounting solution had shifted just enough that the pins were arcing against the chassis frame. We spent the next six hours stripping the whole rig down to test for motherboard shorts. You might want to consider how much stress that puts on the traces. It was a complete disaster and he ended up having to RMA his power supply too. Ngl, it really makes you think about the structural integrity of these modern massive cards... TL;DR: My friend almost burned his house down fiddling with a vertical setup and it turned into a massive, expensive ordeal.