When you say "the default doorbell chime plays inside", what exactly do you mean? The seasonal themes are supposed to play on your Google Nest or Home speaker IF you have "Visitor announcements" enabled for your doorbell, but there is no way for Google Nest to get your mechanical indoor doorbell chime to make any sound except "Ding Dong". Those mechanical indoor doorbell chimes are physically incapable of doing anything else. And if you have an indoor electronic doorbell chime, there doesn't seem to be any interface to make those play a seasonal theme either; that would depend on the physical capabilities of each electronic doorbell chime.
Just checking in to see how the conversation is going. It sounds like you may be talking about doorbell themes that are generally seasonal. You can learn about seasonal themes here. Please let us know if you have any further questions or concerns.