Agree with PPs re things like Duolingo, whilst potentially giving you a good level, probably won’t make you fluent and spending time in a country where the language is spoken is key.
I studied Spanish at uni, spent a lot of time travelling alone in South America, taught English in Ecuador for a short while and have a home in Spain (village in the mountains with no English speakers)........ and I describe myself as “just about” fluent.
It’s not just words, it’s tenses (subjunctive, for example, can be tricky for English speakers as we don’t use it much), colloquialisms, different adjectives, formal/informal pronouns, the list goes on.
My DH is learning Spanish just now and we sometimes watch kids’ tv on YouTube in Spanish (think Peppa Pig). Reverso Context is also a good free app he uses for Spanish - maybe they also do French.
Good luck, though, as too few of we British can be bothered to try.