There already is: once you’ve created a custom page template for the title page for the score (i.e. in the Default Full Score page template set, usually) you can import that individual page template into the Default Part page template set (or whatever page template set you’re using for your parts). That allows you to assign it to pages in layouts using that page template set.
There isn’t an automatic way of telling multiple parts to have specific page templates on e.g. the first and second pages (e.g. for a title page and notation information page); there’s just the option for automatically using the First page template whenever a flow starts at the top of a page.
It would be better and helpful if this may automatically be done when creating a new Dorico file…
You could make a template and start from that every time?
Yes, of course!
The other way might be using the last Dorico project again not to lose my custom symbols, cover page, master pages etc. With this way of working, I have had a terrible experience with Finale. Finale froze while adding a new expression symbol, and the file got corrupted, and I lost all my library… Perhaps. Dorico might be better.
Dorico will definitely do better. Custom symbols (Playing Techniques, Music Symbol edits, etc) can be saved as defaults for any new project. Master page Sets can be exported as .doricolib files; and don’t forget you’ve got the Library Manager to synchronise or copy anything from one file to another.