For anyone who might benefit: they've just released a new version of the "chubby buttons" with upgraded bluetooth.
I had the original on may last bike and it worked great, velcro'd with included strap to my brake cylinder on the handlebars. In short, it connects to your phone and provides five large buttons for play/pause, track +/- and volume +/-. One button press wakes up and connects, and at least with my iPhone 7+ and 11 pro, quite reliable.
Can be used in addition to or without TFT connection.