"let's meet up" is a common usage
throughout the British isles
Two things wrong here. Firstly 'We can meet up anywhere' - the 'up' is redundant and not used in British English. Secondly 'Anywhere' is not a synonym of 'Everywhere'. It's subtle, and is similar to the relationship between the definite and indefinite article. Anywhere suggests a specific known place picked from a random a choice of locations. Everywhere is an unknown place at choosen at random. It also suggests simultaneity. That is we meet at every place at the same time.
A.) Duolingo uses standard american english as its standard
B.) No one said anywhere and everywhere were synonyms, but they both translate to wszędzie in polish
The sentence implies that they are synonyms. However they do not both translate to wszędzie in Polish. Everywhere is wszędzie whereas gdziekolwiek is anywhere.
Well, "spotkać" refers to one meeting, or at least the nearest meeting, "spotykać" would suggest several, possibly regular, meetings. But I guess the difference between them wouldn't really be visible in the English sentence?
I see. I finally found its conjugations online for my glossary. Thank you.
It is incorrect to say, "We can meet everywhere," because a person can only be in one place at a time.
I deleted "everywhere" from 'the best answers', it won't be suggested anymore (may take some time to implement).
I would suggest deleting this example altogether and replacing it with "Możemy spotkać się gdziekolwiek", as "wszędzie" conveys the same meaning as "everywhere" and causes the same problem in Polish as va-diim pointed out in English.
And maybe this one should be translated into "we can meet everywhere", which in both languages might have a different meaning than "gdziekolwiek" or "anywhere". A more philosophical meaning - it is possible that someday we meet someplace, no matter where we go.