If you can log into your router (or just do a search to look at its features), see if there's a VOIP-priority setting for it.
This allows your router to look at headers (and some use more advanced heuristics) and prioritize these as the highest, so that you experience less "drops" and the like, when using WiFi calling/texting.
As
If you really want to pretty much eliminate this, you can get a decent Unifi AP (not really very expensive, surprisingly), and run all your WiFi traffic through it. It does an amazing job of packet priority and the like, and gives coverage like a commercial setup, sort of a pro-sumer type of device, at consumer pricing.
*If this (or another post in this thread) fixes your problem/issue, please mark it as solved, and I'll tag it, to make it easier for others to find the answer(s). Thanks.