I've been using a Bluetooth mouse and a keyboard with my old 2018 iPad Pro for at least 5 years. It's basically our travel computer when we're on vacation. In

I've been using a Bluetooth mouse and a keyboard with my old 2018 iPad Pro for at least 5 years. It's basically our travel computer when we're on vacation. In older versions of iPadOS (it might even have just been iOS back then) you had to enable the mouse under Accessibility to make it work, but in current OS versions it "just works".. You can even cmd-tab between apps and a lot of the keyboard shortcuts you know and love work in most apps.