

There are several more from gog that have offline LAN multiplayer. Skydrift infinity, Wreckfest, ballisticng, overload, project zomboid, starbound, stardew valley, Terraria, torchlight 2, windward. edit: also baldur’s gate 3
also some great open source lan games are hypersomnia, mindustry, openhv, red eclipse, xonotic, warsow, beyond all reason
edit: small caveat that for wreckfest, this patch is needed https://github.com/juj/Wreckfest_GOG_offline_lan_mode_patch
final edit: look into tailscale possibly for your VPN, its easier to do the routing so that only traffic to your LAN goes through that and they will use their own bandwidth for open internet.
with tailscale you can advertise a subnet also