Hey,
The coverage will depend on other radio sending devices on the channels/band, how the physical environment is like what kind of walls, any obstacles etc. It's almost more important to have devices capable of sending back traffic to the accesspoint rather then the accesspoint itself sending out radio waves.
Wifi planning and design is a huge topic that we can discuss in hours.
Here are the datasheet for MR45:
https://meraki.cisco.com/wp-content/uploads/2020/05/meraki_datasheet_MR45.pdf
Look at the Antenna section, 5.4 dBi gain at 2.4 GHz and 6 dBi gain at 5 GHz.
I personally wouldn't place any client farther than 15 meters from the accesspoint, but the accesspoint itself would be capable of sending out farther than that.
/CK