Banking apps are a common example that requires you to be on latest, yet my phone is stuck in Android 10 land.

Whatsapp also no longer works on it, thus the phone is useless.

Which is sad, as it has a great camera, battery life and is very light.

That sounds like LG. Amazing camera and audio and I'm never buying one again.

Should be easy given they haven't made them for over 4 years.

Xiaomi Redmi Note 8.

https://www.gsmarena.com/xiaomi_redmi_note_8-9814.php