First I would like to try to address your problem.

You think it is your power supply unit, and that's quite likely.
Even if you were to suddenly get the computer to work I'd still advise replacing it because a failing power supply can cause very strange issues that often lead people to believe other components are failing.

From the picture you posted it appears to me that you have a pretty standard PSU of maybe 250-350watts? Is it possible to pull one out of another computer that you no longer use maybe? Or a friends old computer even? I know this has most likely crossed your mind, but it's the best suggestion I can give you because it's important for you to diagnose the problem accurately. I think it probably is your PSU though, and they're probably the most universal/common component that most repair shops should have.

I didn't see anywhere in your post a mention of what happens when you try to power on the computer though. Does anything happen at all? I would also look closely at the motherboard, and just look for "popped" capacitors. Or any that are expanding on the tops. Perhaps Like these:

Secondly I want to also identify with your situation as a content creator.
I too create content, but mostly about tech/computers and specifically Linux/open-source software. I've been doing it for maybe 3 years now, and I don't make money from it. I have seen some growth, but nothing that truly justifies the amount of energy I put into it. And there's part of me that feels like I need to just try harder and put MORE energy/time into it in order to maybe succeed.
It's not my job however so I spend my days working at a job that I do not enjoy at all, and don't make a ton of money doing.
I too sometimes become discouraged about my place in life as it's not at all where I thought I would be. Not being hugely successful isn't the worst part, but rather the loneliness. Most of my life I've had many friends, and several girlfriends. My last relationship was a few years ago now, very serious and we were engaged, but it didn't work out. I feel that my solitude now is a result of my age as many friends of mine are now in relationships and starting families.

But I have to remind myself that things can change for the better very quickly, and they can get worse just as quickly. I am fortunate even despite my situation.

You will repair your computer though. I know it will be fixed. Let me know if you can what happens when you try to power it on. I'll try to advise all I can.
Stay positive, and stay strong.