I think finding consistent things outside the house that either you like to do or that help is a good start. I met several of my closest friends in group therapy throughout my adult years, and of all my friendships those have been the longest lasting ones. Two were frequenting restaurants by myself- one I’d go to every Saturday evening and bring a book while I had dinner, and it eventually turned into a book club which then turned into playing animal crossing new leaf together. The other I made friends with someone who worked at a restaurant and we found out we were both Jewish, and now she’s my best friend. Another friend I met shopping and when we see each other like every 6 months we’ll make a plan to get our nails done or go shopping, and I enjoy those occasional friends too.
So just going out to the same places has worked for me. I know that some people find success by joining groups for moms or hiking or game night, and some people use bumble bff and that works for them.