Learn Dutch: Weet jij in hoeverre deze provider transparant is? - Do you know to what extent this provider is transparent?

The phrase in hoeverre (to what extent) introduces an indirect question. In Dutch, indirect questions function as subordinate clauses, which means they trigger verb-final word order. This is why the verb is gets pushed to the end, resulting in deze provider transparant is instead of is deze provider transparant.

Can I use in welke mate instead of in hoeverre?

Yes, in welke mate (to what degree / in what measure) is a perfect synonym for in hoeverre. It functions exactly the same way grammatically and would also send the verb is to the end of the clause. Both are very common in professional or analytical Dutch.

Is the loanword provider used the exact same way as in English?

Not quite. While it is a direct English loanword, in Dutch provider is almost exclusively used for telecom or internet service providers (ISPs). You wouldn't use it to refer to a general supplier of physical goods or other services; for that, you would use leverancier.

Why does the sentence use jij instead of je here?