xize11
27
you can try giving them a reserved ip but the client still request a lease.
but i wonder if the device really disconnects or if it is the internet blocking it, what happens if you reserve it and then ping?
most of these iot devices tunnel through servers remotely and make it manageable from the phone app which basicly just loads up a external webpage with buttons, like @LupusE said it could be a issue with cgnat and they block it remotely.
In some cases it can help with firewall/nat issues but ipv6 also gives alot of complexity some features in gl-inet are still very experimental under ipv6 or features will not work, on the other hand if these iot are matter devices and the claims on reddit hold true that these must require ipv6 then you may want to look into that, as for now if it is not necessary don't use it 