So one last question, do you see any advantage or disadvantage for using either one of these templates? They both work and both do the same thing:
{% set timestamp_no_date = (now().second + (now().minute * 60) + (now().hour * 3600)) %}
{{ (states.input_datetime.lounge_ac_pm_on_time.attributes.timestamp <= timestamp_no_date <= states.input_datetime.lounge_ac_pm_off_time.attributes.timestamp)
and is_state('input_boolean.lounge_ac_pm_automation', 'on') }}
or
{% set d = now().strftime("%Y-%m-%d ") %}
{% set t = now().timestamp() %}
{% set pm_start = strptime(d + states('input_datetime.lounge_ac_pm_on_time'), '%Y-%m-%d %H:%M:%S').timestamp() %}
{% set pm_end = strptime(d + states('input_datetime.lounge_ac_pm_off_time'), '%Y-%m-%d %H:%M:%S').timestamp() %}
{{ (pm_start <= t <= pm_end) and is_state('input_boolean.lounge_ac_pm_automation', 'on') }}