Where are you in the world? What's your connection like? I'm on a 100 megabit downstream (95 nominal) connection in Australia and there are often videos on Peertube that won't load at all for me. YouTube is peered with a local Akamai node or with my ISP and is nearly always instant. The user experience is not like YouTube.

Michigan USA, cheapest package my cable provider offers, which is 30 down, 5 up.

I'm fairly new to Peertube but I haven't found any that won't load. Sometimes they buffer a bit in the first moments, but then they're fine.