You usually have to tighten the cooler mounting mechanism all the way. The cooler mounting pressure is not the problem as to why the CPUs are bending in the middle, the problem is the way the CPU is held in the LGA1700 socket mechanism (the so-called ILM), only being clamped from the long sides. That is what is causing the CPU to bend downwards slightly in the middle.
The best solution would be to replace the ILM with a contact frame, this is the best frame:
https://www.thermal-grizzly.com/en/cpu-contact-frame/s-tg-cf-i
Here you see the reasoning for it (PDF),
https://www.thermal-grizzly.com/media/43/ea/2a/1708697308/TG_Datasheet_CF1314th_EN_TGU20240223.pdf
There's also cheap alternatives like this,
https://www.thermalright.com/product/lga1700-bcf-black-v2/
So, the cooler's screws should be fully tightened for proper mounting pressure and cooling performance. They have no influence on the CPU bending or not, that is only determined by the socket's ILM design. Also see
here and
here. I use an even cheaper method, the "washer mod", with four metal washers of ~0.85 mm height that i had in my toolbox. Works fine too.
Another very important thing, avoid touching the socket pins at all costs, they can bend easily, see
here. Anything you do around the socket, including the CPU installation itself, that's the most critical part of building the PC. Because we probably get a couple people each week which accidentally bent some socket pins during that.
