My honest opinion is to satisfy both charitable works AND woodworking by possibly finding or starting an organization similar to the ramp building that Scott M mentioned. Especially since we are not able to do outreach events right now.
I bought one called a tilt box by Beall Tool Co. I made sure my table was set to 90 and my blade was square. Tried to use it to set my bevel angles and I never got the same reading twice. I went back to my block of wood and plastic protractor.
When you tape joints ( or anything really) the trick is paint from the tape to the wood. Start by burnishing the tape down especially the edges, then start your paint ON the tape and brush towards the wood. That way you’re not pushing paint under the tape. I hope I explained that clearly.