Well, it would really be helpful if you would upload a video, buddy! It would help us better determine if you are doing it improperly that would cause finger exhaustion. Pulloffs are usually gentle on the fingers, and even for a beginner shouldn’t cause too much strain or tension. When you place your finger on the fret for the string you wish to pull off with (in your example, 10-8-7 on the high E string), make sure you actually push down to sound the note on the 10th fret, and then you actually pull your finger down and off. It’s a subtle pull-down. But most beginners approach pull-offs as simply lifting the finger off the string, resulting in a poor sound quality and improper finger movement, which can cause exhaustion.
Think of it like plucking a string. That’s kind of what you’re doing. Press down on the string on the fret, and then just softly “yank” it off to “pluck” it.
If you’re still confused, upload a quick 20 second video of you doing it (if you can) and we can further help you from there