Looping through element queries directly has been deprecated
For your first issue, if you are not paginating then your {% else %} should be:

{% set pageEntries = entries.all() %}


So that the query gets executed. In full:

{% if pagination is defined and pagination == true %}
        {% paginate entries as pageInfo, pageEntries %}
    {% else %}
        {% set pageEntries = entries.all() %}
    {% endif %}


Regarding the update to your question, it's the same thing.

Until you add .all() to your featuredEvents query (or any query), it's like the query hasn't run yet. Adding .all() executes the query.

Craft is smart enough to still run it without .all() but it will warn you hence the deprecation warning.

You should read more about element queries and how to execute them.