There’s lots of YouTube videos about this but basically: you can specify routing.
Meshtastic has terrible defaults (every node rebroadcasts everything, every node sends telemetry), which makes sense in the backwoods but not anywhere close to civilisation.
This, combined with the 10% duty cycle limitation on the used frequencies is the main issue, I believe. Once the 10% are used up, a node basically has to go dead until it falls below 10% again. And with lots of messages about battery levels and other telemetry being sent and relayed, those 10% get used up fast.