I tried building a master node
All day was spent on it. But...

It had returned to WATCHDOG_EXPIRED from the temporary ENABLED
Whether Sentinel has not been introduced correctly or is fundamentally wrong ...

I want to confirm but there is a barrier of words and it is difficult.
If you are getting WATCHDOG_EXPIRED, then sentinel is not running properly (try running it manually from the command line to see what output you get).
However, you will still get masternode payments if you are either ENABLED or WATCHDOG_EXPIRED statuses.
Situation has not changed, but because the reward even WATCHDOG_EXPIRED is coming in, leave it as is.