For a beast like this go with 32 GB of ram for sure. Also i see you went with a 4000mhz kit which is nice. But keep in mind timings also matter. A 3600Mghz 16CL kit will perform way better than a 4000Mghz 20CL kit in a given situation.

That power suppy needs to be changed get a gold or above rated one. 750+ watts wouldn't hurt.

Also i would like to suggest waiting for a higher VRAM option on the 3080 like me (3080 Ti or Super whatever it will be). For a gaming rig like this you are looking about 2k 144hz to 4k 60hz without issues. This means in the future you will need more than 10 GB of VRAM on your GPU as the games don't really give a crap about it anymore. Buying a 10 GB GPU with the power of 3080 is nothing but being a idiot at this point.