I tend to agree. MESH networks are over-hyped and overpriced. If the idea is to get seamless roaming, that's one of the most over-stated claims for MESH systems. Seamless roaming depends mostly on the device, not the router or system and most devices don't support MESH protocols well, if at all. Neither do some of the cheap MESH systems. In field studies, most MESH systems provide little or no advantage over using a router configured as an access point or repeater. In some cases, the router outperformed the MESH system by a significant margin. In addition, some newer routers support MESH directly and work better than dedicated MESH systems. In any event, a MESH repeater will not work as a MESH system with a router that does not itself support MESH. MESH promises may become reality one day but that day is not here yet for most MESH devices. The ones that do perform well are currently very expensive.
If you don't have any dead spots, you don't need MESH in the first place. Smaller homes are best served by a single, centrally located router or access point. Using a separate access point for devices is not a bad idea and could improve wifi performance significantly. I just would make it completely separate, with a different SSID, as adding a wifi repeater of any kind will degrade overall wifi performance. An AC3100 or AC3150 router configured as an access point is probably the best bet. Hardwire it using ethernet to the main router and place it as centrally in the house as possible. If you think MESH may still be required, make sure the router is a tri-band AC AC5300 model that supports MESH and also supports the maker's other MESH products. Note that those exact numbers can be important since they indicate 4x4 capability which is the current best technology available for throughput and range. Tri-band is important since it can provide a dedicated backhaul which doubles the throughput of a wifi repeater.