Unless an abundance of internal storage is a priority for you, 256GB should be enough. This model has a large 6.43-inch touchscreen.
From Amazon
Xiaomi Xia Poco M4 Pro 256-8-4 bk Poco M4 Pro 256/8 Power Black
Gadcet
Xiaomi POCO M4 Pro - Smartphone 256GB, 8GB RAM, Dual Sim, Power Black - Unlocked, New