@Brego, I subscribe what you have been said so far. It’s very important that you don’t limit that boost to your self-esteem you may receive from the outside to have a love partner. Deeper and meaningful connections are more likely to come from casual ones. And when not, you will have the opportunity to meet people to share a time with.

Then, it’s also very important (I would say, the most important) to work on yourself.
This thought you have about your fear people not finding you appealing is not fair with you. I know you feel this fear deeply but it’s not fair or truth. I’m sure there will be people you will be able to connect with. It’s only that some of us find it harder because our own circumstances. The only fact that you are thinking about you being rejected is already a strong brake for you so much that you don’t see the time to leave the house.
What about figuring some little goals that make you leave the house little by little. My advise is to put a date to achieve these goals and think very well, the steps to give to achieve these goals. They must be orientated to your interests according to the possibilities your city offers you.

For example, let’s say you want to work on your body and be fitter.
This is the goal to achieve in let’s suppose, six months.
One step might be to have things ready to go out and take a walk four or five in a week.
All this is only an example.
When the time arrives. You already have the tracksuit, the shoes and all ready to go on the next step, go out for a fast walk.
I put the first step because from your post it seems you see hard to go out.
After you make a habit of going to walk.
You can go to the next step, for example, in these same walks you can stop and ask for information in a nearby gym to join later.

Well, this is only an example.

Also, setting some other goals to help you with getting the other (the social ones) could may be orientated to create other habits in your life as reducing your online time.

Hope it can help you. Good luck!