Yes, if it's like my 2020 3 ( bet it is ), it's programmable through vehicle settings. When delivered it was annoying to have to use door switch or fob to let my wife in on the passenger side after I get in with just pulling the door handle. Now all four doors unlock when my outside door handle is operated.Depends on how you set it up. If the setting is "one click front doors two clicks all doors" the remote key fob will work that way but the touch pad on the door handle will only open the front doors no matter how you operate it. If the setting is "one click for all doors" then one click of the key fob will open (unlock) all doors as will one touch of the sensor in the door handle. This is how my USA version (Premium) works. I am not sure if the UK version works exactly the same way.
Yes, valid consideration, my wife doesn't want our cx 5 programmed that way for the same reason.The reason that it set up with having to click twice to open the remaing doors is for safety. That way, when you just unlock the driver's door and the others remain locked, especially on the other side, nobody can open the door and jump in or grab something out of it.
We thought about reprogramming it to unlock all four with one click but decided against it since it is my wife's daily driver.