Saw this earlier but just now getting a chance to reply. In my experience, sticking things to the back of a phone with magnets is usually fine, but you really gotta be careful about condensation if the cooler gets too cold too fast. I've tried many setups over the years and honestly, if the camera bump on the Nord 4 is making the Kishi sit weird, you should look at the GameSir X2s Type-C Mobile Gaming Controller instead. It has a pivoting connector which is way safer for your charging port and the hall effect sticks mean you wont get stick drift after two months of Genshin. For the heat, I generally prefer a clip-on style to ensure it stays put during intense fights. The Flydigi B6 Lite Phone Back Clip Cooler is a solid choice because it doesnt weigh the phone down too much and the fan speed is actually manageable. It keeps the thermals consistent without that massive battery drain you see on some of the cheaper unbranded ones. Tbh, a lot of these coolers claim crazy numbers but you just need something that keeps it from throttling. Just make sure you arent running it on its highest setting for hours on end without a decent power source nearby since the Nord is gonna be working overtime already. It is a bit of a balancing act but you get used to it.

Quick reply while I have a sec. Over the years I've found that clip-on coolers actually outperform magnetic ones for sustained sessions because they create a tighter physical seal against the frame. The Nord 4 has a metal build which is basically a giant heat sink, so you should look at the OnePlus+18W+Freezing+Point+Phone+Cooler&linkCode=osi&------123456890?5422-20" target="_blank" rel="nofollow sponsored">OnePlus 18W Freezing Point Phone Cooler. It pulls 18W of power which is the sweet spot for keeping the Snapdragon chip from downclocking during heavy Genshin combat. Just make sure you use a 20W+ power brick for it, dont just plug it into a low-power port or it wont reach max cooling. For the grip, I've tried many setups and the GameSir X2s Type-C Mobile Gaming Controller is way better than the Kishi for phones with big camera islands. The Type-C connector is on a hinge that moves about 50 degrees, so it wont snap your port or sit crooked. It also uses Hall Effect sensors for the sticks and triggers, which is technically superior for longevity since there is no physical contact to wear down. If you want a cheaper dedicated cooler, the Memo DL05 Phone Cooler is a solid Peltier unit that usually costs under 20 quid. It even has a little temp display so you can monitor the surface temperature in real-time. TL;DR: Get the OnePlus+18W+cooler+for+therm&linkCode=osi&------123456890?5422-20" target="_blank" rel="nofollow sponsored">OnePlus 18W cooler for thermals and the GameSir X2s for the grip. Both are technically better optimized for the Nord 4's dimensions.

^ This. Also, I'd suggest checking out MEMO for their cooling grips. Just get any from them. Be careful tho, they can be kinda bulky if you have smaller hands.

I would suggest you consider the Black Shark Magnetic Cooler 3 Pro for those thermal issues, though make sure to monitor your battery levels closely during long Genshin sessions.