I am looking for motor suggestions/information for my next line of indoor police drones.

I work for IHMC, a not for profit research institute, and I am supplying my local and surrounding county officers with outdoor and indoor drones,
https://www.ihmc.us/pensacola-police-drone-program/

The outdoor drones are pretty straight forward, (heavy lift, long flight times, thermal and rgb cameras...) but the indoor drones are a little different than what people usually go for.
Our indoor drones are small and our meant for going into situations that are dangerous for the officers to enter(active shooters, barricaded suspects)

Te specs for our current drone are as follows.: 3"inch props, lumenier 1306-7 4000kv motors, 4s 2250 lipo. The all up weight 660 grams and my flight time 10 minutes.

This drone does not have nor require the power to shoot up into the sky in a split second like most drones this size, but does need to be able to carry extra weight, currently i can also lift a 400 gram cell phone and deliver to a suspect in a building.

The reason I am coming on here is I would like to improve upon my design and I am wanting to increase the size of the drone slightly to a 4"inch prop to get a little longer flight time and lifting capacity. seeing as how speed and power are not my main concern, but rather flight time for a heavy drone, it has been a little difficult to figure out what motors i should be using, any recommendations for the best motors for a heavy 4" prop drone to get the longest flight time would be greatly appreciated. I am also thinking of going with 6s lipos instead of 4s unless someone convinces me otherwise.

Tmotor f20 or f30's I would probably go with the f30 so they would be more powerful but you wouldn't use the extra oomph and just use them for efficiency

Your best course of action is to do you own motor and prop testing. Its gonna be tedious, but the expected flying environment and mission profile demand it.