LanguageTool - Spelling/Grammar Checker like Gramarly.

Service URL: https://lang.darkmyre.dev/v2

Brave:

Install the browser extension from here: https://chrome.google.com/webstore/detail/grammar-spell-checker-%E2%80%94-l/oldceeleldhonbafppcapldpdifcinji?utm_source=lt-homepage

Once installed, click the Jigsaw icon in the browser bar (top-right), then “Grammar and Spell Checker…”. Click the cog icon, scroll right to the bottom and expand the "Advanced Settings (only for professional users)" section. Select “Other Server” and enter the Service URL from above.

Edge

Install the browser extension from here: Grammar & Spell Checker — LanguageTool - Microsoft Edge Addons. Click the LT icon in the browser bar (top right), then click the cog icon. Scroll right to the bottom and expand the “Advanced Settings (only for professional users)" section. Select “Other Server” and enter the Service URL from above.