Changes to Engagement Plan Templates in Salesforce only affect newly created Engagement Plans. Here's why:
Template Changes Application:
When an Engagement Plan Template is modified, the changes are not retroactively applied to existing Engagement Plans. Only new plans created after the modification will reflect the changes.
Create New Engagement Plans:
For the development manager to see the changes, new Engagement Plans need to be created using the updated template. Existing plans will retain the configuration they had at the time of creation.
Communicate Changes:
Inform relevant stakeholders about this behavior to manage expectations and plan accordingly. Consider cloning existing Engagement Plans if updates are necessary, applying the new template configurations.
Review Documentation:
Refer to Salesforce documentation on Engagement Plans for detailed information on how templates and plan instances work.
Reference:
Salesforce Engagement Plan Documentation
Salesforce Nonprofit Success Pack (NPSP) Resources
Salesforce Trailhead: Configure Nonprofit Success Pack Engagement Plans

To search for nonprofit user groups in a particular region or state, an admin should use the Trailblazer Community:
Access Trailblazer Community:
Go to the Trailblazer Community website: trailblazer.salesforce.com.
Search for User Groups:
Use the search functionality to look for user groups. You can enter keywords related to your region, state, or specific interests such as "nonprofit user groups." You can also filter search results by location to find groups relevant to your area.
Join Relevant Groups:
Review the list of user groups and join the ones that are most relevant to your needs.
Engaging with these groups allows you to connect with other nonprofit Salesforce users, share best practices, and stay informed about local events and meetups.
The Trailblazer Community is a valuable resource for finding and connecting with regional nonprofit user groups.
Reference:
Trailblazer Community: trailblazer.salesforce.com
Salesforce Help: Community User Groups

Explanation
https://powerofus.force.com/s/article/NPSP-Disable-Trigger-Handlers#ariaid-title3

myTrailhead is the best solution for a nonprofit organization that wants to train and test its employees on various skills such as brand messaging, creating support cases for IT, and publishing online videos. myTrailhead provides a customized learning experience that can be tailored to specific needs and allows for interactive and engaging training modules. This solution also includes testing capabilities to assess employee understanding and track progress over time.
Reference:
Nonprofit Cloud Consultant Guide: myTrailhead is recommended for creating customized and engaging training modules that can be tracked and assessed over time.