Yes, you can use a foam brush, which I did 6 years ago on Red Oak slats. Goes on too thick, so dries too slow to flip without waiting hours and dries a bit milky. These poly finishes are stronger when super thin coats. Brushing took days and lots of sanding, and just not happy on these small parts. I have brushed kitchen cabinet frames and sprayed the doors, but in my own home took a day to mask and sprayed the boxes 2 coats in less than 1 hour and came out perfect.
I don't have a garage or yard, so painting happens in my covered carport. I would risk death if I got paint on the house with my projects since sometimes spray colors.
I used 3/4" PVC and 3-way elbows from HD and painter's plastic. I made mine about 8' x 6' so I could fit household doors inside, as I sprayed mine different colors on each side to match the walls. Weird but I like white trim with doors to match the walls so they disappear.
These clips are for greenhouses and quick vs painter's tape to attach plastic. Assembles/disassembles in 10 minutes and becomes a bundle of PVC and a box of fittings.
Booth is not like painting a car where you need dust free just to protect your garage or house with this GF since it dries so damn fast. In less than 1 minute dust will not stick.