Ways to build up endurance faster?

I’ve been playing consistently for a few weeks now and I have found that my face gets tired and I lose the strength to play a lot of notes after an hour or so of practice

I am very aware to not push the trumpet into my face so when this happens I just move to practice lower notes below C. Is this a good idea?

But what are some ways I can build my endurance other than just keep playing? I don’t really want to stop playing but I do want to build my face muscles correctly.

Thanks!