For some reason I had both sim slots active though having only one sim card installed. When disabling sim2, I could reduce network start time to 30 second.
This is a very unpleasant but unfortunately normal feature of SFOS. I tested right now and switched to flight mode and back after 15 seconds, then it needs 1min 10sec to find the mobile network again. Very long, but this was always this way since I have SFOS (5 yrs).
edit:
also having network lags when starting Android apps…
This is also an old issue and as i now read from you, not fixed in latest version.
workaround: let aas run, close Android app that finds no network, restart network by Sailfish Utilities, restart Android app. Works mostly for me.