And re your 2nd question….I have been learning (because you are still doing it)

I prefer on my own, or even by myself. That shows us that you’re teaching yourself. If you say alone, it implies more that you have nobody near you as you study

Yes, you can definitely say, “I have been learning English on my own since 2022.” “On my own” is indeed more natural here than "alone." “I have been learning” is better than “I am learning” when you specify a time since starting (like “since 2022”) to show that the learning is ongoing. So the sentence should be: "I have been learning English on my own since 2022." Nice job catching that!

In this case we use more " on my own "

"Alone" is grammatically okay since it can serve as an adverb, but as others have said the meaning could be ambiguous. "On my own" would sound more natural. The Present Perfect tense (or the Present Perfect Continuous tense) is needed in that construction because "since 2022" is a time period that we're still in. A lot of adverbs and adverb phrases trigger the Present Perfect for that reason: recently, lately, in the last few days, etc. I would recommend: I'm learning English on my own. (no time frame is specified) vs. I've been learning English on my own since 2022. ("since 2022" is a time period that we're still in)