You mean the crests in their hearts that they given up even before 02 which was the explanation why they couldn't reach ultimate (perfect) level in 02?
The Holy Doggo vs ophanimon debate is a very old thing that lives till this day because Bandai and Toei love teasing us or are bad at communicating or both.
Officially Hikari's mega level was Holy Doggo, then the PSP game happened and gave her Ophanimon, then tri merch happened and gave her holy doggo again, then Movie 5 poster happened and gave her Ophanimon again. Its this constant back and forth, nothing makes sense, who animated that Tailmon evolution in Part 4? what is happening?