For extra modesty with your skirts, may I recommend a pair of bloomers and possibly a petticoat? Underneath?
I have a pair of bloomers similar to the ones linked, and two of the petticoats linked. Not only do they help with modesty, they also help keep you warm!
https://www.amazon.com/dp/B07FC7CDP9/ref=cm_sw_em_r_mt_dp_V7CD1DT5KS16HE295V9M?_encoding=UTF8&psc=1