Why 25 MB isn't really 25 MB
Gmail's 25 MB limit applies to the encoded email. Attachments are encoded for sending, which makes them roughly a third larger, so a video needs to be about 18 MB or less to attach. Anything bigger is turned into a Google Drive link instead.
Attachment or Drive link?
A Drive link works, but the recipient needs access, the link can break and the video isn't in their inbox. An attached file just works — in any mail app, offline, forever.