I was going to say PeakD is robust when it comes to drafts. However I use Obsidian to research, curate links and then assemble posts that much like yourself, can be pasted into the web interface using any device.
I’m hoping to refine this process even more when I get time, so that pulling disparate notes together can become a total doddle. Not quite there but the process is evolving.
Obsidian looks interesting, i might have to try it. The sync feature looks nice but looks like you have to pay a subscription fee for that. I don't want that feature that bad :). If I really want to work on a single post from multiple devices then I'll drop it in google drive.
If you use GitHub at all that’s another option. Such as if you’re paying for that already, as I am. I’ve used their sync but recently decided to boycott subscription based services full-stop and now use Obsidian on one device. Will look at returning to the GitHub approach