Agreed you need a native English speaker. You need an educated one with a familiarity with the subject matter. You will still be left with infelicities in the final result. I did French-English translation about fluid control valves for Elliot-Automation in Alsace decades ago, I met all the criteria, and I could still see problems with the result, but not find acceptable ways to remedy them.

Under NO circumstances trust Microsnot to achieve a result that is (a) accurate or (b) English.

Part of the problem is that there are, regrettably, many English speakers, some educated, who seem happy with what other English speakers will regard as utter solecisms. Examples are split infinitives, "try and" in stead of "try to" and numbers of "alternatives" that exceed two.

The English usage of "which" and "that" also differs from the AAmerican, but although I feel the difference when I see it, I am not sure that I could enunciate a rule.