50 self-hosted sites. Must I create them one by one, add to WP app one-by-one?

I currently have 10 self-hosted WordPress sites, but I own 100 domain names and I expect 50 will become websites. All domains already have the correct DNS.

Are bulk operations possible on any host? With my host I will need to do the following one-by-one, 40 times:
– assign the domain (create the domain within my hosting account)
– create a WordPress installation
– copy the generated password to a spreadsheet (to upload once to lastpass)
– add each domain name and username and password to the WordPress Android app.
– add the plugins I want (I want the same 15 plugins on almost all the sites)
– add the theme I want

I know (well, believe) that upon creating the WordPress installation, my host (Bluehost) will add my new WordPress site to jetpack so I can access all sites by logging in thru WordPress.com, but that leaves some functions missing – I prefer the interface I get when I log into the specific site.

Is there a more efficient way to do all this?
My host does not have a way to do any of it in bulk.
Is there a way to make it so every installation comes pre-loaded with a specified theme and a set of pre-specified plugins?

I know about WordPress multi-site. I don’t think it helps with these issues. Besides, multi-site seems inappropriate for me. “MainWP” might be a more appropriate alternative approach (my tests so far have not convinced me), but again, I don’t think it helps automate or bulk-operate any of the steps I mentioned here.

Thoughts?

Thanks