Intermittent text issues with SMS

I'm really frustrated with iphone intermittent texting issues, only when sending to a group of mixed iphones and androids. I think iPhone has a serious problem switching between iMessage and SMS. At times I can't even send a simple YES response. (I don't think size of text is a factor). I think APPLE needs to fix a software defect. This is intermittent but frequent and very frustrating. Prior to retirement, I was a software tester and am quite certain this is a defect.

Since I have friends with iPhones in the very text strings I mention who have no issues, it is reasonable to believe it could have to do with model, release, carrier, etc.

I am using an iPhone SE (the older one). The IOS is 14.2. My carrier is T-Mobile (I don't think it is a carrier issue). I am almost always using my home WIFI and have WIFI calling set to "on" (my house is in a dead zone, I make calls all of the time with no issues and I believe this variable might be important). I see this frequently as an internet complaint and it is usually answered with work-arounds, none of which work or should not be necessary. Please take this seriously.