Happy Holidays riboflavin1234 - I don't blame you for not wanting to venture out into the world a few days after Christmas. Are you still having this problem with your texts? I can't imagine that this is a good time of year to be unable to send messages (not that there's any great time for that). The troubleshooting you tried so far looks great - I noticed you stopped just shy of a Master Reset... did you try that the last time this happened? Are there any third party messaging apps that you've installed that do work?
On a bright note, you can Contact Us for a replacement SIM instead of going to the physical store to get one, although it definitely takes a little longer. I am concerned that a SIM would cause this problem twice, though, especially since you replaced it so recently. From what you've mentioned about your phone, it sounds like it should still be covered under the manufacturer's warranty as long as it was purchased new, so at least if it's a defect you'll be able to have a replacement ordered in the store, but we'd love to help you prevent that if possible.
Hey there! How is your text messaging app working these days? Did you wind up trying any troubleshooting steps or did you stop by the store after all? Please let us know how it's going - we'd love to help if we can.