Enterprise WiFi For 4000 Sq ft Office

Hey guys,

We have a open floor plan 4000 sq ft office with 50 users who strictly use WiFi. We are in a saturated office building, and currently using 2 ubiquiti AC routers with a 100mb fiber inet line.

We are still suffering from dropped signals and slow performance. We ran a spectrum scan, and i do see a lot of WiFi networks. I chose one that is not used as much (1 other router on that network it seems) yet we still suffer from issues.

Is there a more enterprise WiFI setup i can go with to help solve these issues??