Hi, some of the hunting wagon code isn't mine to share (menu base) and its a very bad learning resource tbh so I do plan on rewriting it some day and releasing it. But I'm more than happy to share any of the specifics of the hunting wagon part.
Looks like you had the wrong group hash, it should be 1754796591 (0x6898122F).
Exact code I use:
wagon_menu_prompt = UI::_UIPROMPT_REGISTER_BEGIN();
UI::_UIPROMPT_SET_CONTROL_ACTION(wagon_menu_prompt, GAMEPLAY::GET_HASH_KEY("INPUT_FRONTEND_LS"));
UI::_UIPROMPT_SET_TEXT(wagon_menu_prompt, _CREATE_VAR_STRING(10, "LITERAL_STRING", "Hunting Wagon"));
UI::_UIPROMPT_SET_PRIORITY(wagon_menu_prompt, 1);
UI::_UIPROMPT_SET_TRANSPORT_MODE(wagon_menu_prompt, 0);
UI::_UIPROMPT_SET_ATTRIBUTE(wagon_menu_prompt, 18, 1);
UI::_UIPROMPT_SET_STANDARDIZED_HOLD_MODE(wagon_menu_prompt, 1704213876);
UI::_UIPROMPT_REGISTER_END(wagon_menu_prompt);
UI::_UIPROMPT_SET_ENABLED(wagon_menu_prompt, true);
UI::_UIPROMPT_SET_VISIBLE(wagon_menu_prompt, true);
UI::_UIPROMPT_SET_GROUP(wagon_menu_prompt, 1754796591, 0);