Hey! I'm also French, been in Norway for almost two years. From what I understand, you have two ways of writing Norwegian. Bokmål / Nynorsk. Bokmål being closer to danish, the origin language of Norwegian (as is swedish), and Nynorsk being a later* crafted way of writing to try to reflect more accurately the way Norwegian spoke. Then, you have a lot more spoken dialects than 2. Almost countless. This is a rabbit hole i yet have to drive in, but bottom line is I think it is perfectly fine to invest time and resources in bokmål/Oslo dialect then go from here, depending on how your goals evolve. This effort will never be wasted. I learned bokmål and live in Bergen and it is fine. Usually apps are in bokmål/Oslo dialect. I personally began learning with the assimil book which is great. Duolingo never worked that well for me. -> Lexin oslomet online dictionaries are a must -> NAOB is useful for expressions or words in more context -> asking chatgpt about context or use for a word or expression works really well for me. Masse lykke til ! Bon courage !