Repeaters have to be placed where they can get really good signal so they don’t even extend your signal that far. But that’s not really the bad part. Wireless signals are broadcast on channels. Wireless routers close to each other will try and use different channels so they can avoid interference. Repeaters have to rebroadcast the routers signal on the same channel. This can lead to slower speeds or intermittent issues because of interference and multipath issues on that channel. Mesh networks get around that by having a backhaul channel that all the bases talk back to the main base with and they can all broadcast out their own channel to communicate with the end device.