additionally it would be great if custom templates could also be used during import, currently the generic CSV import only supports 8 predefined fields (name,url,email,username,password,note,totp,vault)

As a new user I'm surprised that I can't save my custom item as a template for use in multiple items. Creating a new item from scratch every time for certain things I use is both time consuming and annoying.

Surely, you are using "templates" to mean what is more commonly known as a user-defined composite type (like a data structure in C or a record in Pascal).

I would refrain from using "template" for a user-defined composite type to preclude any conflation with programming language (PL) "generic types" (C++ uses "templates" to refer to its generic typing facilities, e.g.). The naming of constructs varies across implementations. Consider "field name", "database column name", "data member name" used across various technologies, e.g.

"data type": number, text, binary blob, composite type, etc.
"composite type": user-defined aggregate (i.e., data grouping) data type
"data member name" (AKA, "field name"): a name chosen for identifying/accessing specific data within a composite data type.

structure Person {
text name
number age
Address home_address
Address work_address
}

where,

"Person" is the user-defined composite data type name
"text" and "number" are built-in type names
"Address" is a user-defined composite type name
"name", "age", "home_address", "work_address" are the structure's data member names

Add facilities to associate user-defined operations/behaviors (verb) with the user-defined composite data (noun) and you've created (or exposed to the end user) an object-oriented programming facility.

I've looked at PP's "other type" facility just briefly today based on posts in this forum indicating that it is implemented in the latest PP version (why I manually had to download the desktop PP app without notification and installation from the app directly is unknown to me, and another commonly expected facility lacking in PP for some reason, though I recall getting an email indicating improvements in PP were available) so I don't have any comment on that yet.

(I don't write code much anymore, but learned to code and programming language implementation tech decades ago).

Next stop, a full-fledged type system and scripting language used across all Proton products?

That is why I am still using Enpass. I have some PFX files with login data that I need to register. I've made a template with the following

- Accountnumber
- Certificate Numer (login)
- Password
- 2FA
- Recovery PIN
- Recovery email

Upload - cert.pfx

Wish we could use that in proton. Create a template and keep the template. Make sure we can set divider lines for a nice view.