What you are describing is bang-bang mode. If the hub isn't connected to a smart-device running the powered-up app and the connected motor isn't a train motor, it's how a powered up hub connected with a powered up remote behaves.
It's reasonably straight-forward to create a project in the powered-up app to implement gradual speed control, but I dislike this option because it requires you to have an additional device (smartphone or tablet) running along side your moc.
My go to solution for this is Pybricks. It installs alternative firmware on your hub, allowing you to upload python programs to the hub. For example here is code to control the LEGO Technic Audi RS Q e-tron (42160) with the powered up remote.