In other words: you're not willing to pay enough for such a feature to make anyone capable of building it make it for you.
There just aren't enough people like you to support self-hosted $4/month product and you're not willing to spend $2000/month for self-hosted version.
So your options are not using the product at all or using hosted, incredibly cheap, version.
And many people don't have the time or skill to "just build it yourself," so when something awesome like this comes along that looks really appealing, you get people asking for self-hosted options.
You can either log-in with Google account (which you most likely already have) or via 2fa mechanism where they send an expiring login link to your e-mail address.
There are no password and therefore nothing to hack.
Why not? Is there something wrong with wanting a local, self-hosted tool? Or wanting to pay for it instead of building it yourself?
For some people like me that's a basic condition to even consider a tool.
Do you publish the progress of this project you're working on for interested persons to keep track or should we wait until you're ready to unveil it?
https://gitlab.com/equalos/equal
I've been trying to get it into a nice state, but it is a process.
The problem is that making a good interface is a though and long task. It's not done with crapping something together which then barfs out some file. That's people just can't build it themself, because it would be months and years to reach a good quality.
The demand for local&selfhosted on the other side is clear: people don't trust the companies. Companies peek into your data, sell them to other, or just disappear one day. With something under your control this will not happen.
There also might be a valid demand from those who would want to use the features of a collaboration suite like this for internal projects but find themselves beholden to internal or even client-demanded security/data retention policies.
Why is it every time something like Notion is mentioned, there is always someone who wants "local, self-hosted, Markdown"? Just build it yourself.
This clearly shows you have no understanding of the product at hand. Notion is so incredibly powerful that Markdown doesn't even scratch the surface here.