Oh OP, I thought of one more thing this morning.

When I started to attend my sangha, I found I had a hard time doing the standard 30 minute silent mediations. I found I was over-reliant on Papa Sam's 10/20 minute guided meditations. I would encourage you to make sure you can comfortably meditate for 30 minutes before attending a sangha.

Same goes for retreats. Some retreats will assume you can just casually sit for 20-40 minutes. Also, if you are going on retreat, make sure you can practice and enjoy walking meditation.

At least for me, the thing that helped me with this more intense sitting was growing my samatha practice - which I feel like Sam downplays the importance of a bit. I know follow a standard meditation practice of samatha -> open awareness.

Happy to expand on this if you want to learn more.