The only place the Monzo app is officially available on Android is the Google Play Store.
Due to sanctions, Huawei devices do not ship with the Google Play Store anymore.
If you’re in the market for an Android phone with a good performance to cost ratio I’d recommend Xiaomi. I’m currently using a Mi 10t Lite 5G because my Pixel broke, and it’s a steal at £200 with 5G support and a 120Hz refresh rate display.