[Buying Advice] Standalone router vs Mesh network vs Access point : Good coverage for 1500 sft Clinic

Have started a clinic in a 1500 sft space.
Current internet requirements are met with a 4G Jio SIM in a TP-Link Archer MR200 router, which is decent but not reliable enough for a commercial application.
Got an ACT connection 500mbps with a AX1500 Wifi 6 router. I am planning to upgrade from this.

Requirement :

Wifi internet coverage for the entire space of 1500 sft with no dead spaces

Need a single SSID to interconnect various devices, like printer, lab computer, reception POS and computer etc. So no repeaters or multiple different routers etc which provide different SSIDs.

Short list :

I have been looking at installing an Access point or a Mesh network but am divided between the two.

Any suggestions of which would be superior are welcome.

Thanks in advance