One caveat about Grammarly, which I also use: Use it as a guide, not as the final answer. If there's any question for me at all about Grammarly's decision making, I have found that Google has gone pretty hard-core AI on its search box. You can actually ask a question about specific grammar usage (even if you query with the specific sentence and words you are curious about), and it will guide you to the correct answer.

Grammarly doesn't always get things right. It's absolutely essential for the gotchas and misspellings, but it struggles with context.