It's great to hear a perspective from someone who is a non-native speaker. Thanks for taking the time to read the post and share your thoughts.
I hope the readability will help you. I can imagine without a native English speaking friend to proofread everything for you, it could be difficult to catch mistakes using the basic spelling & grammar tool in Microsoft Word. I hope these tools will help you, and maybe give Grammarly a shot too. It may have some new suggestions that Word has never given you.
Best wishes!