Is it possible to change the view type form "content" to "content revision"?
Technically speaking, the type of a view corresponds to the base table against which a database query is executed. This means that it sets the stage, so to speak, for the data that is going to be collected. All fields, filters, sort options etc. are configured in relation to that starting point.

Since changing the view type would mean changing the base table, you would be replacing the foundation your view is built on. This a tricky thing to do, because the data you are collecting may not relate to the new base table as it did to the old base table. (In a more radical example, imagine turning a Content view, which retrieves the node ID, into a User view. That would break because users do not have a node ID.)

So is it completely impossible? Maybe not, especially because node and node revisions are somewhat similar. When you look at the exported configuration (YAML markup) of a "Content" view, you will see a line base_table: node_field_data. In a "Content revisions" view you will find the line base_table: node_field_revision. If I had to try this (disclaimer: I never did!), I would do the following:


Duplicate the view I want to change (so I don't lose the original) and save it without changing anything
Go to /admin/config/development/configuration/single/export to get the config YAML of the duplicated view
Copy the config and paste it into a text editor
Change base_table: node_field_data to base_table: node_field_revision
Delete the duplicated view
Copy the edited YAML from your text editor and import it via /admin/config/development/configuration/single/import
Hope that the import doesn't generate errors
Go to the configuration screen of your newly imported view, see if it reports problems, and try to make it work


Good luck. When you do try the above, I would love to read if it worked for you.