How do I send a photo album by email to a non Apple user?
How can I send a photo album by email to friends who do not have Apple products?
Email has not been designed to support very large attachments.
You could create a shared album and enable the "public website" option for the shared album, then mail the link to the shared album, see: How to share albums in Photos on your iPhone, iPad, and Mac - Apple Support. Even users without Apple Devices can download photos from a shared album. You do not need a paid iCloud Storage subscription to use shared albums.
If you are using iCloud Photos Library, you can share selected photos as a folder on iCloud Drive and mail the link to this folder.