You’re mixing up UTC with displaying time in 24-hour format.
UTC is an abbreviation for Coordinated Universal Time (in French). It is the successor to Greenwich Mean Time. It represents ‘time zone zero’.
23:15:00 is simply time expressed using a 24-hour clock (45 minutes before midnight or 11:15 PM). Time expressed using a 24-hour clock doesn’t imply it is UTC or EST or any other time zone unless it is explicitly indicated.
Anyway, the principal reason the automation isn’t triggering at the appointed time (Home Assistant uses a 24-hour clock so 10:36:00 means in the morning and in your local time zone) was explained by Petro. Your automation is defined in the wrong place and is ignored by Home Assistant.