Dear PJAckson76,
I would return to the place you got your phone first: mine was Verizon and even Apple support will tell you there are bad production lots of the iPhone 11 Pro there. If you have a good relationship with them there and can get all your data copied to a new version of the phone I would do that.
If Verizon is not the option, backup your iPhone 11 Pro with iMazing on the laptop/desktop of your choice and then go to the local Apple store. Ask them to run the typical diagnostics tests on your iPhone and then run the DFU(when running DFU, all data will be wiped, so be prepared). If they still find no problems; still ask them to replace the phone entirely with a new one. They will honor this because they know they need to do so. There are bad production lots out there.
When you get the new phone, have them run all the tests on the new phone and if it checks out ok, take it home and test it on your Wi-Fi first *** BEFORE *** restoring you data to it from iMazing. If the Speedtest results give you what you need you are all set to go ahead and restore from iMazing and test again.
If your results are still inconsistent and short of your expectations, it is time to change your router settings. Come back on this site and provide a router and model number and I will provide some tips which may help your situation.
I wish you luck with this, I know how irritating it can be.....but, the above process has solved this for me.
