Free and Open Source Software

I've been on the hunt for a Google Keep replacement and the most obvious choice is Quillpad. However it can only sync with Nextcloud and that functionality is somewhat broken. For example, if I create a To Do list in Quillpad, I can of course check the boxes as items are completed. I can do the same in the Nextcloud instance under Tasks. But if I create a To Do list in Nextcloud, you cannot interact with them in Quillpad after it syncs. They're displayed, but you can't do anything with them.

All that said, the other choices were Zoho Notebooks (don't trust them) and Carnet (weirdly slow on my phone) as far as similar apps. Quillpad still seems to be the best. Is there a way to get an app that only syncs with Nextcloud to sync with something else? DavX, Webdav, Caldav, etc? The reason I ask is because I wanted to like Nextcloud, but my admittedly older server (HP Microserver G8) struggles even with the optimized builds and it just has way more features than I need. I have a feeling the answer is no, but thought I'd ask anyway before I continue my hunt.