K9 mail on Android since many years and Thunderbird on laptop, also since many years. Also use Gmail, Yahoo Mail.

I have been to Iceland recently and tap water is absolutely fine to drink directly and preferred. No one there buys water. Just make sure you drink the cold water and not the hot one as the hot is from natural thermal springs so may contain some minerals I belive. Just carry your own bottles and you can fill up the cold water from anywhere, even restaurants will refill free.

Using Nova Prime since many years now. Very satisfied, never felt the need to use anything else

I use Keepaas for PC and KeepassXC on Android, sync with FTP. I use autotype feature of Keepass when I want to login on the browser

Which phone did you upgrade to? I also have the 7T and quite happy with it except for brightness outdoors