I found all of the IKEA buttons quite good and they are really affordable. They are not FOSS like you requested but they use ZigBee and they work really well with HA. The light bulbs are good, too.

I still use a ConBee II for the ZigBee connection but I think there are better options available now. I bought it years ago.

Google is killing off its proposal for “Web Environment Integrity API” as a new web standard, though Android phones may still have to deal with it.

That is literally the first sentence of the linked article. I think this is one of the things how it comes back.

The sync on Android itself is pretty stable. Every now and then it throws errors about not being able to sync but those could be because of bad reception.

The Nextcloud app on Android has another weird error for me. It doesn’t show the content of a notification (like “Update for app xyz available”) but “NEXTCLOUD_NOTIFICATION”. I tried to resolve it using different approaches from the internet but it followed me even to a new phone. I just gave up for the time being.

The sync with iOS is somewhat bad. To get all the images from my wife’s phone to the cloud I have to plug it in, deactivate screen timeout, and open the app. Sync will stop once I close the app.

Last but not least compared to iCloud/Google Photos watching and browsing the photos on a device is just way slower. I understand why that is but in the end it’s just an annoyance making the switch harder for people in my family. They understand why I am passionate about selfhosting and privacy but they still have a reasonable expectation that things just work.

All in all nothing really severe. Little annoyances along the way. I am still quite happy with the solution all in all.

Nextcloud app. It works alright.

On iOS it’s a different story though… (my wife has an iPhone)