@PageBaileyandbookanOR
That's interesting about younger friends. I am almost 60 and am lucky enough to have some good friends. But they are all my age or older. A couple of my closest friends are 70 and 75 - we were work colleagues back in my 20s and just clicked. One died recently aged 80.
I enjoy the company of people of all ages but have been unable to turn younger people into friends, just as you describe. With no younger close relatives, I can foresee a potentially lonely old age as well as having to deal with doctors and care homes alone (things I have been able to support older relatives and friends with over the years).
OP, I recommend being a bit brave. Once lockdown is over, and restrictions allow, suggest coffee to all kinds of people even if they seem unpromising as friends, and say yes to any tentative suggestions from others.. You may be surprised, and if not, then they may have friends you click more with or at least you have had a morning out and practice in chatting!
I think people are attracted to friendly people so building up acquaintances is a good start.
I also echo the suggestion of joining a formal ''make friends' group - one of my work colleagues found herself really alone through changed life circumstances about 10 years ago but just bit the bullet and joined one. Pre-lockdown she had a great social life, a lot of casual friends she could rely on to go to the theatre or an event with, and a few closer friends have grown within that.