Hi TMB1,
If you are using the latest version of AccountRight online with a subscription, then it wont be possible to access this in an offline mode (without an internet connection).
There have been a lot of improvements with starlink and some mobile providers increasing network coverage, but if you are regularly working for extended periods of time without internet, you would most likely need to keep manual records and then update your MYOB once you have a connection again.
We do complete testing with customers before changes are made as well, and often this is through data directly based on how customers use the software and in many cases, with a group of customers in an early access program.