We don't have anything to nag us, but the grandparents and aunts and uncles all have Nixplay[0] frames that we regularly update with photos of the kids.
I bought one for India. My parents don't have a wifi but they have a smart phone with a data plan. Hoping they will be able to enable access point on their phone to sync photos.
Honestly I considered trying to hack one but just never managed to put it on the schedule. Early models had some quirks but now they're reliable enough that I haven't found any pain points that would compel me to open one up so if I ever get around to it it'll be just for funsies.
If you're pushing to fewer than 5 frames per account then their free tier works fine. They used to cap the free tier to 1000 photos (we just deleted older photos to keep the collection fresh) but now the free tier supports unlimited photos. I'm sure some day they'll go bust or get bought and it'll stop working but I feel like we've already gotten our money's worth out of it.
this won't be a popular suggestion but it works for us: We got the grandparents Nest Home Hub display. It's LCD and there's a switch to disable mic and camera but it works really well for photo sharing.
[0] https://www.nixplay.com/