My advice would be to consider throttling the bandwidth on the guest network and also block ports and use a restricted dns server with that vlan.

You can't vet everyone's devices so you want to be proactive.

Pretty sure you can block all the Chinese IPs and still disclose information to China. Discord for example is a massive business which China had heavily invested in. Part of their constitution is Chinese owned companies must disclose information.

https://www.vintageisthenewold.com/game-pedia/is-discord-owned-by-tencent#:~:text=Tencent%2C%20the%20owner%20of%20Discord,and%20retain%20personal%20information%20indefinitely.

That's not alot. At my old home I used to use DFS until a radar plane flew over and everyone's wifi defaulted to the same channel. The Linksys WRT32X was just trash in a fancy case though.