I have made my own internal demo that is a standard build to easily show off progressions, but my game is not at all suitable for a public demo.
I have answered this question a few times, but here are the reasons why :
There is a difference between a content driven game that uses an available and complete framework (like most plateformers, rts, FPS etc...) and a game that is built on as a completely new one.
The first one you can have a functionnal game within a day and most of the work will be on adding more features on top of it. You can make a playable demo almost on day one If you smartly gather some assets. The originality of such project is on unique features that deviate a bit from the genre and tons of content or an original story. This needs a a very polyvalent team.
The second needs a huge amount of work making the engine of the beast, then once it reaches the level of a viable game framework it is possible to add content and make the game playable. It is basically 90% of coding. It is good only when it is something that doesn't simply reinvent the wheel.
I am on this second case, It means I will release a private alpha probably at the end of 2020 or early 2021. After the alpha, it is likely that it'll be the most impressive phase of development for the public as adding content is much much more visible.
TL/DR : No. It'll be an alpha release.