One one hand I don't want to be the final authority, but on the other hand, I'd like to share my point of view on how to learn English. The English language is not secret knowledge; it is just a lot of hard training. One of the most important bullets is constantly improving English. You should do it from day to day if you want to approach result. It must not loathe torture for you, It means that you should find out something interesting in that process.
Vocabulary, grammar, reading & audition are possible to train at home without a teacher. It depends on your patience, determination & systematicity. Let's go to tools.
This tools will not help you if you do nothing with it. If you work hard then few months or years later, as a result, you should have big enough passive vocabulary & be able to understand the English voice. The main idea of that stage is that you must do something constantly every day & it should be interesting for you.
At the next stage, I suppose that you would like to improve your speaking. First of all, you should convert thoughts into English speech(not translate!!!). How to deal with it?
Q: Is it possible to speak English without speaking?
Well, you can read & write at home without help, but for speaking you must talk. There are some services for that, i.e. preply, skyeng, italki, etc. From my point of view, at the beginning you don't have to speak with a native speaker, it's ok just talk with somebody with C2 level.
How to learn continuously? It's a sophisticated question. I use something like GTD/S.M.A.R.T.
No pain, no gain.
When I was in primary school, I visited a private English coach for a year or two. However, there were no major results. A bit later, there were English lessons, when I was in secondary school, unfortunately, I was not really good in English learning. As a result, when I had graduated from school, I heard that grammar exist, could not talk at all, was able to read with a dictionary. When I was studying at a university, I had been involved in IT, so I started to read IT docs in English. Sometimes, I used to do it with a dictionary.
Just before I graduate, I had applied for international IT company. It was funny & frightful. I had to talk & chat with workmates during the day, so my English was improving forcedly & sharply. i.e.
In 2017 I applied for an international IT company and started an intermediate course again… On one hand It was strange because I finished it 6 years ago, but on the other hand, I finished it without any major efforts. However, I've been doing English tasks myself. i.e.:
One of the bests ways is to go to an English school, usually, they can estimate your level for free before a course. However, there are a lot of online tests:
The main problem is that there are no free online audition tests.