The tricky part about anxiety is it could have many causes, but the most common cause by far is just accidentally developing a pattern of thinking that creates anxiety and getting stuck there. You've identified what the problem is, you've decided you want to change it, and now you're gathering information before you make plans and take action to begin changing it.
None of this will be as applicable to your specific situation as you would get from seeing a therapist. Consider doing what we call "opposite action." If you have the urge to doomscroll, intentionally do the opposite and go outside for a walk. If you want to spend the day alone in your room, instead go to a restaurant and eat by yourself but in public. Small things like this will help you break out of your patterns and begin to realize the world is not a very scary place. One of the most common misconceptions is that all the people out there will notice all your faults. In reality, most people couldn't care less about your faults, and you would be surprised how many people out there would love to connect with you. There are always going to be negative interactions sometimes, but try not to let those get to you and just move on.
Also, set a strict cutoff time at night for your devices, and stick with it. If you have trouble sleeping, take a melatonin, read a calming book, drink something warm, whatever you need to do, but keep your phone off. It's hard to overstate the negative effects doomscrolling and a lack of sleep are probably having on your mental health
I worked in a hospital for a long time and oversaw an entire team of people whose only job was to interface and argue with insurance companies. For my small hospital, we had 7 people doing this averaging $85-$90K per year each.
And don't get me started on unfunded care. Since we live in Texas, which has not expanded Medicaid, there are a ton of people who end up in the hospital with no insurance and who will never pay a cent because they literally can't. Hospitals try to make up that funding gap by raising rates on everyone who does pay. We're already paying for other people's healthcare this way, I wish we would just nationalize health insurance and eliminate insurance companies entirely.