I had exactly this issue (twice) in a Mercedes GLB hire car a few years ago. As you say, it’s very unsettling as you have no idea how fast you are going, which is no defence if you get done for speeding. This is one of the unfortunate aspects of the ever increasing drive towards digitalisation and touch screens although, in the case of the latter (which are dangerous IMHO) it’s good to see that some manufacturers are listening to customer feedback and starting to reintroduce physical buttons for the most regularly used functions.
I love technology and all that it can do, and I’m no old fogey, but I think it’s gone way too far in cars and you now feel like you’re driving a computer on wheels. I’m seriously considering buying a second hand car that pre-empts a lot of these changes (inc nanny state bings and bongs) to rediscover the joy of driving!