since the latest IOS I have multiple issues with messages not being delivered, sometimes to groups, sometimes to single people, doesnt matter if on wi-fi or cellular (although there is almost no signal at my house) do I need to check a setting??

I certainly would not risk messing with settings until I had investigated the most likely suspect - poor cellular signal. You have commented about the very low cellular signal at your home, so I suggest the first attempt would be to make a few tests from other locations where the signal is better.

A settings problem would be a "hard fault" always present under all conditions. If it works away from home there is nothing wrong with your settings. If it is intermittent and sometimes works / sometimes not either at home or away, there is nothing wrong with your settings.