I also have a Hero Alpha build . I purchased the Alpha back when it came out and I absolutely love it. I havent really had any trouble with Asus software, but I noticed that all the software on the disc was outdated when I got my mobo, so instead of installing from the supplied disc, I went directly to Asus.com, looked up the H8 Alpha and downloaded all the software I wanted from there. There are also other important updates for the mobo's chipset, Sound, SSD drivers, UEFI bios,etc. on there .
Like Nate said, Since were not totally sure where the lag is coming from, its probably best to do a fresh install and start over, since your build is new. Then we can go through each step and rule out possible causes for the lag.
We have a somewhat similar setup. Id be happy to share my UEFI settings and some links to a few guides I used to to get everything running nice and smooth. Ive got my 6600k Oc'd at 4.7ghz now and computer runs smooth as silk.
Also, what kind of storage device are you installing windows on? SSD? M.2? Did u install from a USB ? That information might also allow us to help you better.
ASUS ROG Z790 Apex Encore | i9 14900ks | | G. Skill Trident Z5 8000 | 2x WD SN850x 4gb | Asus Strix RTX 4080 OC| Asus ROG Thor 1200w | Windows 11 Pro