The Hammerhead Karoo 3 also has the best of both worlds (buttons and a touch screen).
The Karoo 3 is extremely easy to use—highly intuitive—with great GPS. Recommended!
While the RRP is above the OP’s budget, it’s available on sale for close to it.
Although Shimano has stopped the Di2 integration I think or had so I definitely wouldn't buy one in my case.