On macOS, Tot [0] is a great app that replaces the "working memory dot txt" format that Cal Newport likes. The upshot with Tot is that you get a fixed number of pages, and they're synchronized via iCloud. So, you can add to your "working memory text file" from anywhere you have an iOS or macOS device, and it's simple enough that it can't grow into a more complex system.
I wanted to love Tot, but its iCloud sync just isn’t good. In my first week or so of ownership, sync between my devices stopped working a couple of times. I followed the instructions (https://support.iconfactory.com/kb/tot/icloud-sync-not-worki...), and that worked for a while, but then it un-synced again. I ended up getting a refund for it.
In the end, I stuck with Drafts. It doesn’t have the 7-item feature/gimmick, and it’s not as pretty, but it’s been 100% rock solid for me for years.
[0]: https://tot.rocks/