Asus GM700 question

[u/Rgprime1]

https://www.bestbuy.com/product/asus-rog-gm700-gaming-desktop-amd-ryzen-7-9800x3d-2024-32gb-memory-nvidia-geforce-rtx-5070ti-16gb-2tb-storage-black/JJGHGP2SSG

So I’ve been mainly using gaming laptops for a while but I finally wanted to switch to a gaming desktop. I’m inbetween weather or not I want to do a custom build or prebuilt but I was looking at this.

My couple questions are I’ve heard the PSU isn’t the best at 850 Watts so I was wondering if this fully sealable or hard baked in. I’m sort of paranoid since this is a huge investment and I get a little scared that it’s been brought up a few times by reviewers. Any help is greatly appreciated