My personal concern isn't just with the card itself bending a bit (though that is also a concern), but more with all the weight these larger and heavier cards are putting on the PCI Express slot.
Apparently my current one (just under 1,600 grams) is maybe but half of what some of the very heavy ones are, and I'm still concerned to the point I wouldn't use it without support. Anything that extends the length of an ATX motherboard and then about a quarter more of that length beyond, and is three slots, that is the point where I'd not want to go without support.
Well, you don't have to worry too much about the weight because the steel I/O bracket is more than strong enough to hold the card in place enough that the slot won't get damaged. The sagging of cards is a much bigger threat to the cards themselves as it applies torsion to the end of the PCIe interface (aka the foot) which can cause cracking.
A long time ago, Powercolor made a card that was just completely over the top and insane called the
PowerColor Devil 13 Dual Core R9 290X and it was an absolute beast of a card:
This thing had a TDP of 580W (just look at the 4 PCIe Supplementary Power Connectors) and
weighed MORE THAN 2kg! The Gigabyte GeForce RTX 4070 Gaming OC (which is what I assume your card is based on the pic you included) has a fully packaged weight
of just under 1.8kg so your card isn't overly-heavy by modern standards. It's by no means a light card but when it comes to sag, length is actually more important than weight because the longer the card, the more leverage its weight has. My XFX Radeon RX 5700 XT THICC-III used to sag visibly at the end, but that card was insanely long at 315mm while weighing about 1.6kg. That sagging didn't cause any harm to any motherboard that held it nor did it damage or disfigure the card itself in any way. Your card is a bit heavier (~200g) but is also a bit shorter (1.5cm) so I really don't think that it will do any damage to the motherboard even if it does sag. Having said that,
Gigabyte had a problem with cards cracking just above their feet so if anything, I would say to get some kind of support for your card's sake. I believe that your motherboard will be just fine.
