You shouldn’t worry about Docker Machines. It is outdated technology, that was the main way for managing the servers in Wappler.
Now Wappler has switched to a better approach - using API from hosting providers. Resource Manager allows you exactly this.
Only downside of Resource Manager is that in its current state it only supports Digital Ocean, Hetzner and Linode.
If you are ok with that, then you can forget about Docker Machines and only focus on Resource Manager.
I am still using Docker Machines, because I need to deploy my project on VPS from a provider that is not listed.
I hope that eventually Resource Manager will support this option too, so Docker Machines don’t needed anymore at all.
About Docker. There are other options for deployment, but I believe Docker is an optimal way now, especially if you are not experienced in this area.
There is no problem for you to switch from Digital Ocean to another provider in future.
But in that case you better migrate your database too, you will have to do it yourself or with the help of provider’s support, but anyway it is not a big deal.
And yes, you can change the project’s hosting type in the future too. You can switch from Docker hosting to FTP, or to Heroku, or something else. But I doubt it will be relevant to you in the near future.
Overall, it seem like you choose the right way to start:
Wappler hosting for local target,
Docker hosting for remote targets (by Digital Ocean),
Managed Databases (by Digital Ocean).
All this is managed in Wappler by the Resource Manager.
All these project settings can be easily changed in the future, if needed, so do not worry about it.
I am not sure that I fully understood your question, so feel free to ask more, if I have missed something.