I am all for having a fitted radio rather than a remote bluetooth speaker especially if you already have one fitted and are just looking to swap out the head unit. My question would be why do you want DAB+? As far as I am concerned all I want my car radio to do is connect to my phone. I have dab radio apps on my phone, I have Spotify etc on my phone, I have saved/purchased music on my phone, and I can then as a bonus make hands free calls on my phone. I am usually all for old fashioned things but your phone does everything and more that a radio does you just need a connection to get it to play through the car speakers.
I have just fitted this system to mine:
Pioneer MVH-S520BT
It is the newer version of what I had previously. my requirements were very specific but at the same time very broad. All I wanted was the ability to connect two phone for hands free (work+personal), an external microphone to combat general defender driving noise, and the ability to play whatever my phone was playing. This is all I used on my last one and all I have used on this one. the only other "requirement" was an aesthetic one where I preferably wanted a green display to matched the green illumination of a standard defender dash.
If you work out the criteria you actually require it is far easier to slim down the huge offering of head units to one that will actually serve your purpose. E.g if you don't want CD player the unit tends to be about half the depth making it easier to fit into the dash etc. If one of your criteria is built in DAB+ that is fine most units should allow that but do you have a DAB+ compatible aerial fitted?
If you don't have anything fitted currently I can also give speaker and wiring recommendations as I was starting from scratch after a fire. If you already have something fitted then it should just be a straight plug and play swap.