N95 masks cannot be made at home. Special materials are required. Those protect you from other people. Ordinary medical procedure masks can be made at home, but those are only useful in protecting other people from your coughs and sneezes if you already have the Virus.
I saw a tutorial on how to make a mask that gave the actual “N” rating in comparison to store bought masks. It was lower, as you say, but some protection is better than none, imo, since I’ve read how sick you get may depend upon the initial virus load you receive. In other words, if you are infected with a smaller number of virus particles, your body has longer to gear up for a fight against it.