I have never been to a u3a meeting but my local u3a has a group for ‘members on their own’ for people who are single, separated, divorced and widowed.
If you like music, have a look at your local cafes and bars, see whether any of them feature live jazz night shows.
I remember once reading on Gransnet - a lady went on a Cunard cruise with her husband. Every time she went to eat on her own, she was approached by her fellow male passengers.
Not sure about internet dating, there is the risk of ‘meeting’ romance scammers.
Sorry to read about the sexual assaults. I used to work in a predominately male industry, the men I met including my former male colleagues are decent guys. However, you cannot afford to be sensitive if you work with men.
I had a discussion with my female friends once, some of them are married, some on their own, but all of them said they are not interested in pursing a new relationship now or in the future. They said at our age, we will end up either as a nurse or a purse.