Grammarly is quite good - https://www.grammarly.com/ The ProWritingAid app is a great tool. https://prowritingaid.com/ The free version offers editing for up to 500 words at a time and many useful features. I also use the Hemingway app, which is not a grammar checker per se, but helps me detect complex sentences, common errors, adverbs and passive voice. http://www.hemingwayapp.com/ Hth
Do you use the free or the paid version? I have subscribed to the paid version a while ago and I find it mostly helpful. The only inconvenience would be that you can't use Grammarly on iPad, but I suppose that's not an issue for most people.