In theory if you leave the country without AP you lose TPS.When you renew they will ask for you I94 which will show that you did not parole and that will cause issue while renewing. That applies to any status even H1b anytime you leave country you have to have AP.

I went last year in TPS while on F1. My F1 visa was expired and I did not chose to renew it.

I suggest you to take the AP go to Nepal get a F1 renewal and come back on TPS AP. (Although I do not know the consequences of this)