Find a company angle on it. Sharing low effort pics of pumpkins that say happy Halloween doesn’t look great but maybe arrange for staff to do a pumpkin carving competition (from home, if better?) and share pics from it? Last year, we did an after hours event where everyone did a pumpkin, it was a good team building exercise, made for some fun content and showed to people looking in that we were a nice place to work. It might not be possible this year, but find the angle.