The tabletops also seems a bit too thin and wiggly for my taste, but, honestly, for LAN parties with chill people you personally know — it's ok
As for the actual host setup with a singular disk image — great job! LAN gaming centres do something similar with their setups, with some differences (a lot of centres either use Windows-based diskless solutions that mount vhdx files as drives remotely over iSCSI, or use ZFS-based snapshotting, which is my personal favourite)
But all in all, seems like my dream house :)
I own a chain of LAN gaming centres, so the feedback is definitely skewered into the business perspective quite a bit
I ended up putting together my own thing. I saw various products that seemed like they might be what I wanted but they always seemed... sketchy.
CCBoot is a Windows Server-based diskless solution I mentioned, and they also provide CCDisk, which can do "hybrid" mode — where there is a small SSD in every PC with base OS pre-installed and pre-configured, which then mounts an iSCSI game drive
GGRock is a fantastic product, in my opinion. It is pricy, but where as CCBoot relies heavily on knowing it's inner workings, GGRock is pretty much turnkey solution
There is also CCu Cloud Update, which I have heard of, but didn't try myself, since they sell licenses only in Asia, from what I remember
LANGAME Premium is an addon for LAN centre ERP system, which is basically an ITAAS solution based on TrueNAS. Of all paid offerings that one is my favourite so far — but you have to use their ERP and actually run a business for it to be cost-effective
NetX provides an all-in-one (router, traffic filter and iSCSI target) NUC-like server with pre-configured software on a subscription basis. I am most skeptical of that just on the basis that, from my research, two NVMe drives can't really handle the load from a fully occupied 40+ machines LAN centre. Not for a long time, at least
...and homebrew, of course. I myself am running a homebrew ZFS-based system which I'm extremely happy with
In your case, I'd go with building my own thing too. Does not take a lot of time if you know the inner workings and you have no additional OPEX for your room :)