Co-founder of Wheelmap here. Great to see it mentioned! Wheelmap is 10 years old this year and has 1 Million places from OSM (and synced back) and 1.3 million places from ca 130 other sources which we aggregated as one API for others to use as well. You can find more info on https://www.accessibility.cloud/.
We also try to standardize accessibility data on https://a11yjson.org and https://www.w3.org/community/lda/
Happy to answer any questions (but have bad internet connectivity for the next few hours)