In a strange coincidence (or maybe its actually inevitable given the timing) I also saw a podcast with Matklad of Tigerbeetle and had a similar idea--I've been working on a massively multiplayer game as a hobby project, also built in zig, also fully allocating all memory at startup, and also had an experience almost identical to OP's. In my case both my client and server are in Zig. Zig is pretty great at doing performant game code (rendering and physics on the client) ... it's less great on the server compared to Go (early days and fewer batteries included, fewer things just work out of the box ... but you can find pretty much everything you need for a game server with a little hunting and pecking and a debugging few build issues).

Zig also works "okay" with vibe coding. Golang works much better (maybe a function of the models I use (primarily through Cursor) or maybe its that there's less Zig code out in the wild for models to scrape and learn from, or maybe idiomatic Zig just isn't a thing yet the way it is with Go. Not quite sure.