Yes. But before you do that, check if there’s an update available for the OS. Go to Settings > System > System update. If an update is offered, I advise to install it, as this will likely solve the problem.
“Android 11” is not sufficiently precise unfortunately. To talk to the operator or FP support you will require the exact version. To find out, go to Settings > About phone > Build number (right at the bottom). The latest release seems to have been 8901.4.A.0021.0
If your operator is happy with the build number and says Vo LTE should be working, then contactsupport to tell official Fairphone support about it.