I solved this problem without having to spend money on a hardware wallet by
1- removing SIM card and factory-resetting my old phone, immediately putting it into airplane mode (wi-fi, bluetooth and everything else also manually disabled) and ENCRYPTING WITH STRONG PASSWORD (not draw pattern);
2- installing Electrum via APK stored on micro-SD;
3- generating new wallet in this air-gapped phone, then I imported x-pub to everyday brand new phone.
Now I can see balance, receive bitcoin and create unsigned transactions on the connected phone, then old phone signs transactions via QR-code.
Cheap and easy.
Ok, not bad, you basically have a DIY hardware wallet. Still not as much secure (physical access to phone and chip-off technique among others) and certainly not as convenient to use as a commercial hardware wallet.... But yes, its ok.
Hardware wallets are now less than $100 anyways.... That's still cheap, and easier.
Not forgetting that I always have Electrum's seed (written down, memorized, hidden, scrambled within books, etc)