I’m from Vietnam. I’ve been in the UK for 10 years now. When I met my English husband 13 years ago at 19 I knew 0 English. We communicated using machine translation. So that’s when I started learning English. Fast forward to present day after immersion, living in an English speaking country, formal study, etc. and I’d say my writing and listening (understanding) are good, but my speaking and reading are still bad. I kind of gave up on trying to become fluent at this point.
I learnt to speak French by living there for a year or so but I still cannot read it at all beyond short sentences because how a word sounds is different than how it looks.
As for English, I think both learning English and English speakers learning other languages is extra hard because English is such a hodge podge of random bits of other syntaxes and structures. Its a mess of a language in lots of respects making it hard to learn and hard for native speakers to get past the messiness and learn a better structured language.