My Threshold Power doesn't match with XERT Garmin App

I have few issues.
First of all, my threshold power from XERT doesn’t match the “What’s my FTP” IQ app. Both are way off
Second of all, my threshold power from XERT is not even close to what my real FTP is

My Actual FTP is 226. my XERT says that is 240 & “What’s my FTP” says is like 202 watts. Both being way off

20 minute FTP test only provides an estimate of your FTP. For many, it’s actually can be very far off, particularly if you have higher/lower relative proportion of fast to slow twitch muscle fibers. In your case, I think the system didn’t have good estimate of your PP so overestimated your last breakthrough by ~10W. If you can keep your PP accurate, you’ll never need to do another FTP test again since the system will pick up your FTP from regular ride data. Good luck!

Sorry if this seems like a dumb question. How can I keep my PP accurate

Something happened, but now xert seems to report my right FTP. Can you shed some light hete

Every once in a while put in a good sprint. See the FAQs. What you see is what happens when a decent PP and not grossly underestimated value is used on your data.