In the
Settings>System>Reset Options menu, select Reset Wi-fi, Mobile, & Bluetooth. You can read a bit more about it here:
https://www.androidpolice.com/how-to...s-and-android/. There are very minor hassles with re-pairing Bluetooth devices and reconnecting with wi-fi networks, but it might help if there's something glitchy with your mobile connection.
RCS is still occasionally glitchy for some users, with reports of text messages not being sent, often to iPhone users (since iPhones don't use RCS). It's supposed to fall back on SMS, but for some reason, that doesn't happen. Turning off RCS chat temporarily (as a troubleshooting step) might help you figure out if that's the issue.