Unfortunately that is very unlikely, as YouTube shorts are served from the same servers as all other content on YouTube, so PiHole can’t tell the difference.
But even for iOS there is uYou+ which can block shorts and I’m sure there will be a similar piece of software for Android.
I have been using a PineTime for quite a while now which is an absolute no-brainer for 27$.
Even if it’s marketed for tech/foss enthusiasts it’s really easy to use, would recommend if you just want simple step tracking and heart rate monitoring.