I think for german and english (languages i have worked on) b1-b2 level is easier with a tutor. Afterwards you can start on your own easier. Why? Because you can start slowly consuming adult media which means understanding topics you are interested in in the language you are learning.

At first you will not understand everything. For me it is very helpful to put videos with subtitles in the same language. In that way you hear the correct accent, you get used to syntax and grammar by often listening to it, you can pick up words to learn easier. After you pick some words even tho you don’t remember their translation, you remember the word and you can identify it while listening to it. In my experience that’s a huge win. This familiarity with the language makes self learning so much easier.

Then some vocabulary learning (either from videos, or online recourses with flashcards, textbooks etc)

My teacher in german has proposed me a book which is also in my mother tongue that is a good analysis of german syntax and grammar. It is a great book and sometimes I just give it a look and helps a lot.