I’m a little late to the party but I had the same phantom text issues on my G2 and G3 a few years ago. SMS images were always iffy and the probability of a text being sent or received was inversely proportional to the importance of it (i.e. important ones would frequently go missing, trivial ones always went through).
There were other nuisance issues that pushed me over the edge and I–rather begrudgingly–upgraded to a G6. It’s not without its flaws but texting has been significantly more reliable since making the switch. The one exception has been group SMS with my cousin’s wife–she’s absolutely not able to see my replies to a group SMS but I can always see hers. Group SMS with my sons seem to work reliably–they’re both on Republic with Moto G(something) phones.
As far as coverage goes, look into GMS vs. CDMA. I just switched my G6 from GMS to CDMA and it’s made a noticeable difference in my reception in some places, including my office where I had to keep it plugged in all day because of the constant battery drain from searching for a tower.
Good luck with the new phones!