Honestly, I'd like to see some science on the bracket design. My card (an ASRock 6900XT, 332mm, 1.78kg per reviews) came with a bracket that's a modestly beefy

Honestly, I'd like to see some science on the bracket design. My card (an ASRock 6900XT, 332mm, 1.78kg per reviews) came with a bracket that's a modestly beefy-looking piece of steel, but it just bolts into two or three more thumbscrew sockets, and the actual contact-point with the card is a glued on rubber bumper that's like 2mm x 15mm and a rubber bumper, so there's opportunity for it to bend or not align with the card well, and the bumper gets unglued, and it blocks all your slots. I ended up getting the type of bracket that's a rod with a little magnetic foot to anchor it to the bottom of the case, and then another foot that the card rests on. Again, this is dependent on how tightly the thumbscrew holds the top foot in place, but hopefully the downward force from the card is being projected straight down the bracket. The right answer is probably to reintroduce flat-mount 'desktop style' cases. There was zero sag risk when I had the build in a CoolerMaster HAF-XB, but it was a bit shallow for a card that big - you couldn't get the card out without disassembling everything and lifting at odd angles while applying enough force to rip the clip off the end of the PCI-E slot. Alternatively, if we could get some collaboration in the industry, they could agree on a standard "max length". I note there are some documents suggesting the maximum length for an ISA or PCI card used to be ~338mm. In that scenario, the cases can be designed with an explicit assumption there will be a 338mm card installed, and there are little support rails at the front to engage a card of about 338mm long. These could help bear the load and ensure the card remained aligned. Ancient PCs had this-- I can recall opening an old Compaq 286 and seeing it stuffed full of "full length" cards neatly fitting into rails in the case. Back then, the cases were desktop and the cards were light, so the rails were more for management and neatness, but there's no reason they couldn't carry weight in a modern revision. I think I've also seen it with some weird OEM builds more recently-- they'll add a metal or plastic shim to the front of a long card so it matches up with rails in the one case it was designed to fit into.