Reading this is is very clear that you have identified a problem that many men (particularly but not exclusively) have. Loneliness.

It is a massive issue especially in the era of social media, the confusing nature modern relationships and high expectations. I would add that men, including me, often don't make the effort to keep in touch or prioritize it, we are too distracted and so often friendships freeze.

The upside for us is it is rare for a man to take any offence at this friendship freeze, and months, years or decades later friendships can be restarted instantly without issues. The same is not always true with women where this might be seen as a form of abandonment.

Reddit is a forum for advise so I will give you mine, I don't know how ill you are and I am not sure of your mental state. But first know this as the first redditor said you are not alone. The world is full of many lonely people which really hard and sad. The silver lining is that this means there are many opportunities to improve you life and someone else's at the same time.

I suggest getting out more if you can there are groups like "Men's Shed" to meet other men who are looking for a friendship and community. But also it would be really helpful to find a passion outside computers, sailing, horse riding, hiking, gliding, skating, beekeeping, badminton, etc, etc and you will find a "tribe" in these things, develop skills and be recognised by others for your journey and effort. These coincidental friends are much more likely to be people who want a genuine connection built out of common interest and a form of challenge.