This is getting out of hand, somebody needs to pull ATX out of the stone age. ATX just wasn't designed to accommodate cards this big and heavy and the cooling is also very inefficient. Case, motheboard, and graphics card manufactures need to get on the same page and start making some revisions to ATX and really ultimately start transiting to some completely new thats built around the concept of the GPU being the most power hungry component in a modern gaming PC (or workstation).
As a stop-gap to a ground up new design put some standoffs on the case (on the motherboard panel), through holes on the motherboard, and add on structural supports on the graphics card that can physically mount to the standoffs on the case so the card is physically supported along more of its axis and not just at one point.
I was thinking this the other day, largely with the concept of the supplementary power cables and how and where they are connected. These cards are thick, huge, heavy, and the cable connector gets to hang out right at a place where, not only does it look ugly, but it has the potential to impede airflow and even add to the stress on the PCIe slot. The ATX design is certainly not ideal for premium hardware. GPUs are one thing, but let’s not forget CPUs needing either a massive, heavy air cooler or a water loop.
If I were to take a stab at this, the board design needs to move the CPU and GPU to the floor of the case, and the supplementary GPU power could ideally be routed through the motherboard through a standardized connection, perhaps through a revised PCIe spec for GPUs. If we must stay vertical, then a standardized GPU support system needs to be laid out.
The 2019 Mac Pro actually does this, where their custom GPU options use an extension slot for powering the card, and there is a support mount on the end of the card to reduce connector stress. The problem is that only their custom cards can take advantage of these changes, but you can still install traditional cards and power them with additional cables. Such a concept would allow for a transition period, but it does mean massive motherboards.