I'd go with the MR36.
The only issue you are likely to run into is with the firmware on clients. The MR36 is WiFi6, while the MR42 is WiFi5. Let's say you are a WiFi6 client. The WiFi6 AP has a weaker signal (further away) than the WiFi5 AP, but you really want to stay connected using WiFi6 because you are also using WiFi6.
Some clients aren't as smart as others at choosing which AP to connect to.