Thank you for reaching out!
The easiest way to achieve this would be to whitelist the operators of your home country. This can be done by first scanning the available operators by navigating to Network → Network Operators → Connection mode: Manual. Start the scan.
After the scan, the desired operator(s) can be added to the whitelist. If you'd rather prefer always having the connection, even if it's not possible to connect to your home country operator, then Connection mode can be set to Manual-Auto, which will prefer your whitelisted operators, but if they're not available, connect to a foreign operator.
A way to check which country operator you're connected to could be by connecting to SSH or CLI and logging in with the username root and the same password as WebUI. Then, run this command:
Theoretically, the only value you should be interested in is MCC, which is the value that identifies the carrier's country using uniquely assigned numbers. This number can be compared with your operator on this website or similar.
I'd also recommend checking out our guide on cell locking, which might be useful in your case.
Let me know if any more information is needed!