alt Hacker NewsMichel Thomas is the answer (or it was for me anyway as someone previously TERRIBLE at languages)
BBC made a documentary about him where he teaches a French gcse to the 6 worst kids in the school, in I think 2 weeks. https://youtube.com/playlist?list=PL94A517B00A16C187&si=4eAv...
He was also in the French resistance, survived concentration camps and is generally a very interesting person.
His successor is https://languagetransfer.org, which is just a labour of love by a genius polyglot and language teacher.
So much so, in fact, that the owners of the Michel Thomas IP tried to sue him for stealing the methodology. The EFF, back when they actually did anything, shredded them.
https://arstechnica.com/tech-policy/2018/07/no-you-cant-pate...
Please check Language Transfer out and support him how you can.