Don't know how to deal with depression and suicidal ideation

It's not the first time I have been depressed. It's like a recurring undercurrent throughout my life. I was depressed for most of my 20s and I had a failed suicide attempt 15 years ago. Last year I was going to kill myself. I chose a foolproof method that couldn't fail and set a date and I arranged to meet with a solicitor to write a will, but it all got disrupted by the sudden lockdowns.

I was on a waiting list with the NHS for counselling, but they phoned me up and told me they couldn't see me any more because they didn't have enough staff, and that if I wanted to kill myself I should call the Samaritans.

I have called Samaritans and other charities a few times and although it's great that these volunteers try to help people, I don't feel like they understand me and I don't like being on the phone. I have emailed them as well but just receive what is mostly a stock response where they tell me to call them.

I don't know what to do any more. I get no enjoyment out of doing things and I don't see the point of anything. It all seems bleak and hopeless and I despair all the time. I have nothing to look forward to. Mainly I hate myself. I have no friends and I am so alone. I feel so empty all the time. I don't even bother eating any more. I don't do anything except sit by myself and wait until I can go to sleep. And sometimes I cry. There is no support available to me.

I have been thinking a lot about quitting my job. I tried going into the office again so that I have some human contact, but I hated it. It was so over-stimulating and I hate being outside in the city centre as well. The smells and sounds and brightness of it stresses me out. I tried going for drinks with my colleagues, but I feel so alone in a room full of people. I feel like they all get along and vibe off each other and I am this weird alien that doesn't belong there, and they don't care whether I am there or not.

I think I need real help from a qualified therapist, preferably one familiar with autism, but I don't know how. I'm still on a very long waiting list for the autism, probably won't get seen until next year, and I don't expect anything to come from it anyway. It seems like there is nothing available to me. I have contacted the doctor so many times. They won't see me face-to-face and the only way to contact them is via a text-based web service where they respond with half a sentence after which I can't reply. There is nothing available to me on the NHS anyway. The waiting lists are all over a year, and I was previously on one and they cancelled it. I don't want to talk to someone on the phone because I find it really difficult.

What can I do?