I got this older fireplace (2004 ish), it has two wall mount switches, blower and igniter. The current physical switch has no AC running through, just a simple dry contact. Are there any Z-wave switches out there that handles simple dry (DC maybe) contacts?
While there may be devices, first check with your local government. In many places it is illegal to use any device which can be operated out of sight for a gas fireplace, including any device which can be operated from a phone app, for safety reasons, unless the fireplace is classified as an in wall heating system and has its own thermostat.
And using something which is a violation of code will also typically void your homeowners insurance if there is an incident.
So just something to check into as part of the project.