Thanks for the extra info. So I think the problem appears to be that you are running around trying to make yourself useful - and if you adopt a servant role, that is how people see you, especially if you aren’t great at putting your views forward.
I think the most useful thing to do right now, rather than worry about making friends is to do a bit of self examination of what you want out of life, and also, why you have ended up fading yourself into the background.
I hate to bring it up but a bit of therapy might be useful, not to fix you, I don’t think you need fixing, but to help figure out what you want out of life - and also why you fade yourself out. Once you know what you want you can start to put yourself in a starring role, everything will get more colourful, and people will want to join in.
This is excellent advice, OP -- not just for you, but for all the people on here who feel as you do, and who automatically go into 'service' mode when they try to make friends, thereby rendering themselves invisible.
Look what you did when you met the pregnant woman in the hairdresser's -- you saw her pregnancy as an opportunity to talk about her, and it sounds as if you didn't talk about yourself at all, which means she leaves the encounter with little or no idea about who you are, so she's not thinking 'Oh, there's that interesting woman who etc etc' when she next runs into you on the road.
I moved countries at the start of 2020, just before the first lockdown, and am obviously setting out to make new friends, as I know no one at all here. The people I am drawn to so far are very different, but they're all thoughtful, interesting to talk to, funny, and often do something for a living that they're passionate about, and generally have a lot going on in their lives. I'm not thinking about what I can do for them to be of use in their life, I'm purely thinking 'Do I want to see more of this person?' They won't all necessarily want to be friends with me, obviously, but that's not a disaster.
You sound as if your sense of yourself as 'invisible' has paralysed you, and you now behave as though you aren't interesting and memorable in your own right.