Multi-platform ones. Don't worry about "native" apps unless it is multi-platform or you'll get too tied to a specific eco-system and won't be able to migrate if you need to.
Generally I agree, that's why I try not to lock myself in as well. However, if you use e.g. a eco-system specific markdown editor with a specific feature set or workflow that feels like it's tailored to you and you have the markdown files, I think it's fine since you can take your data with you when you leave.
I think I would like open formats and protocols instead of the mess with Electron. So like the sibling comment, native markdown editor + a sync folder.