https://xdaforums.com/t/removing-carrier-lock.3903352/

https://xdaforums.com/t/no-root-needed-carrier-unlock-carrie... (I know what the title says, but this procedure is generic to Mediatek and they are also easily rootable)

Look around that site in general, plenty of Android modding information.

Also see "SIM lock" here:

https://gist.github.com/sadiqsalau/865364b344c0b9cb1b418df8b...