1. Open Writer > click File > Templates > Manage Templates.
2. Open context menu of one of the templates.
3. One of the context menu options is entitled "Set As Default". As I know, the word "as" should be in lowercase: according the language rules and as well according to the rest of LibreOffice UI.
Steps to Reproduce:
User Profile Reset: No
I confirm it with
Version: 126.96.36.199.alpha0+ (x64)
Build ID: 758516295e5f69393bd78bb4af6e7214d48ece0b
CPU threads: 4; OS: Windows 10.0 Build 18362; UI render: GL; VCL: win;
Locale: de-DE (de_DE); UI-Language: en-US