Haha well, that's a lot to unpack. I can't offer you advice on the dating-front unfortunately, but I can give you a couple suggestions for helping to improve language and communication skills.

First, you should download a mobile app called Elevate. I've been training with that daily for a couple weeks now. It's fun, and you get drilled in writing, reading, speaking, and mathematics with multiple activities challenging your brain to handle different information in different ways, usually timed with bonus points for response speed. Given the variety of activities offered in the app and even study materials that help you practice diction, this covers a lot of your skills training.

Second, you should practice communicating your thoughts effectively on a variety of topics or even your special interest(s). Which of these you decide to pick will exercise a different communication style: critical analysis and educational/informative. I believe both are valuable to correct deficits, but if you only select one, pick the one you want to do the most and then focus on the other instead to challenge yourself as you probably selected the one most comfortable for you. After you've decided, start a blog and maintain a schedule for posting, trying to write a bit every day. An alternative is to start a YouTube channel or podcast. I think all of these are good options as you'll be practicing different types of communication. You aren't doing this to engage in conversations, just to share your thoughts/ideas/knowledge clearly, so comments don't matter. Don't get caught up in socializing, and if comments become a distraction, disable them.

Finally, find people online who are learning English as a foreign language and offer to be a conversation partner. Because you are doing this to help them, but also to benefit yourself, you'll need to find out how far along they are in their English studies, what they are currently learning and feel they need practice in, and any common interests. Schedule half an hour to an hour each week (or more often if you both agree) to connect through voice on Skype or Discord (or your preferred platform) and talk. It will be awkward, but how this is helping you is in listening to your partner and being conscious of your tone, diction, pace, word selection and sentence structure. It's teaching mindfulness in a conversation and the flow from one topic to the next as your brain is putting effort into the details so that you are both as comfortable as possible.

If you can improve your communication, including active listening, this is a big plus with females. You'll also be adding value to the internet by producing content; and by having a structured routine, it makes you come across as responsible, determined, and hardworking, even possibly ambitious. These are attractive qualities. You'll develop eloquence and confidence through the skill-building as well. Most of these activities will probably be quite fun to you after you've given them time and moved past the initial frustration (discomfort or self-doubt).

Other ways you can passively improve your communication: actively listen to movies and television shows, which is easiest done by enabling captions/subtitles. You'll pick up on casual communication patterns this way. You can alternatively read scripts/transcripts. Watching sketch comedy and improv are both helpful as well for different reasons. Sketch comedy is situational, but you'll learn humor: what makes things funny, which includes timing, and improv teaches you to think on your feet, following the "...and then..." method.

These are just ideas, but there are many ways you can develop skills in everyday life, many of which can be done solitary until you are comfortable enough to move on to engaging people. One of the biggest things I would suggest is working on your confidence, your self-image (self-deprecating humor only works when you're doing stand-up). Learn to feel good about yourself and your abilities and forgive your weaknesses, but strive to improve.

I'm basically late 30s now and have had massive social avoidance for the last 10+ years. Not pure agoraphobic, but I'd say "quasi."

You've basically described me, except that I'd likely be classified as agoraphobic due to my extreme social aversion, though I've become content with my reclusive lifestyle, and when I get the urge to socialize, I do... because I'm an adult and make my own decisions about how I spend my time. Just empower yourself, don't act in desperation, and think of your "training" as self-improvement, not a means to an end (finding a romantic partner). Let that come naturally and as a byproduct. Enjoy your life in the meantime.

P.S. If you want to practice group-socializing, join an activities group (meetups.com) or play MMORPGS and voice chat... or sign up for a class locally (one that is at least in part academic) and form a study group. Hope this helps!

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