Following up to completion, I modified the sensor in packages_unavailable_entities.yaml as follows:
under:
{% set ignored = state_attr('group.ignored_unavailable_entities','entity_id') %}
I added:
{% set ignored2 = state_attr('sensor.disabled_device_entities', 'entities')|regex_replace(find='\[|\]|\{|\}|\'name\':', replace='') %}
and under :
{% set entities = entities|rejectattr('entity_id','in',ignored)
if ignored != none else entities %}
I added:
{% set entities = entities|rejectattr('entity_id','in',ignored2)
if ignored2 != none else entities %}
Checked the configuration, reloaded the template sensors and now my entities of disabled devices are ignored by the sensor.
Iām sure this could be improved but Iām pretty new at Jinja2 and Python.