Yeah, for that threat model, a VLAN is not needed in my opinion:
esphome devices are for sure not data collecting and pihole will block most of the phone homes with a good block list, where possible (like simple smart devices) they are flashed with a local open source version. Still the vast majority are KNX and Zwave which are local only
video cameras are local-only always and have completely blocked internet access via the router
This is probably the biggest threat unpreventable in other ways. Though definitely citation needed for them actually being caught recording conversations lol. People think phones do that too, but it is simply a lot easier (and more importantly, cheaper with a much higher ROI) to make a complete data picture through search/watch history + proximity to other devices.