Do you have anything in common? I do some stuff with my 20 year old daughter and always have - she's incredibly independent (doesn't live at home - moved away for work, doing brilliantly and taking the initiative on career development, supervises interns years older than her, has multiple groups of friends and a long term boyfriend).
I think the key maybe is she compartmentalises - she does certain stuff with her partner, certain stuff with colleagues, certain stuff with one friendship group and certain stuff with her bff. I have a compartment too 🤣☺️ We go to the theatre together and to certain small concerts of a couple of specific bands. These are both interests (the specific bands, and theatre) that her friends and partner don't share. Sometimes she buys the tickets and invites me, sometimes vice versa. We've been away for a couple of nights combined with seeing bands abroad or trips to other cities for plays.
I don't really have much in common with my 18 year old, although spending time together at home is lovely we just don't enjoy the same stuff outside the house, except for one sporting activity where I would be a burden as I'm much slower - I'd absolutely hate that, and anyway if I'm honest it's something I prefer to do alone so I can set my own pace.
I don't think it's personal or something to be hurt about, once they're adults it depends how much you actually have genuinely in common and how your personalities work together.
My mother used to try to cajole me into doing her interests with her, but she wasn't interested in anything I was interested in, or at least not the same aspect of any interest (it's all very well to both like music or cinema but if it's completely different music and completely different types of films it's not an interest in common). By adulthood you have to genuinely want to do the same stuff, it's not like taking little kids to see Toy Story and dragging them to church with you, or whatever.