I went through this exact nightmare with my first massive card. Tried a cheap kit and the sag was so bad it looked like a ramp. I eventually switched to the Cooler Master Universal Vertical GPU Holder Kit V3 PCIe 4.0 and honestly havent looked back. It is built like a tank and handles the weight of a 4080 without flinching. Since you are in a Lian Li case, sticking to their ecosystem is smart. I put a Lian Li O11D EVO Vertical GPU Kit PCIe 4.0 in a build last month and the fitment is perfect because it integrates with the chassis frames. Few technical things to check:

• Ensure the riser is rated for PCIe 4.0 so you dont lose speed.
• Verify it supports 3-slot cards since the 4080 is huge.
• Look for adjustable rails to keep fans away from the glass. Either will definitely save you before your brother shows up.

Regarding what #3 said about Lol I was literally about to post the same thing, I honestly feel your pain. I had issues with one of those generic kits back in the day and unfortunately the sag was so bad it felt like it was gonna tear the motherboard apart. Not as good as expected at all. Since you are using a Lian Li case, honestly just grab one of their own branded kits. You really cant go wrong with them and they are way more reliable than those cheap ones on amazon.

• Check out the official vertical bracket from Lian Li.
• Basically any reputable bracket from Phanteks is also rock solid.
• Just make sure you get a pcie 4.0 riser cable if you can find one within your budget. Honestly, save yourself the headache and just go with parts from the case manufacturer. Trying to save a few bucks on the mount is usually a recipe for disaster with a heavy card like that. Good luck with the build, dont stress too much!

My buddy told me the exact same thing last week. Guess he was right lol.

Lol I was literally about to post the same thing. Glad someone else brought it up.