No, memorize many noun most important. Grammar less Important. Can do food, can do travel, can do tax. Because, noun most important.
Tbh, that's how I learned English. Rudimentary grammar, knew a few words, and then just read with dictionary until I didn't need a dictionary. Also watched a lot of shows until I didn't need subtitles.
Languages are weird like that – if you use them enough, your brain just figures some things out. After all, natural languages are easy enough for toddlers to learn.
Me go market, find juice, say sugar free
nice! sugar free!
me take juice, me take sugar, police take me, why? hell!
I think we have different definitions of “proficient”. :)
Working with ESL people makes it clear that grammar isn't so important. One of my friends would say, instead of "go shopping", would say "make some shoppings". Instead of "it's time to go", he'd say "time for go". All words that started with 's' were pronounced 'ehs', as in "gas ehstation".
The other people at work soon picked those lines up, and we used them regularly amongst ourselves. I still use them decades later!