Home Assistant is awesome, but not ready for the mass-market. It's a fun tech project to setup and one that will require your attention regularly forever-- but on the bright side, it isn't constantly annoying, it works consistently, and it can all work locally so when some Chinese vendor shuts down their servers you aren't left sitting in a dark room.
It's improving at a rapid pace and I can see it being ready for your aunt to use in a couple of years. Not this year, not next.
I set all my relatives up with Apple HomePod Minis and HomeKit, which has expensive hardware (matter is supposed to fix that...) but is largely local and relatively private.