This is a design issue. On most BMW models the cabin air filter is located under the hood next to the firewall and it’s simple to replace. But on this model D filter is located under the glove box. Tools are required and several panels have to be removed from under the dash to access the filters.

Adding to the problem is that the owners manual does not mention the cabin air filter anywhere.

I consider it abusive by BMW to have a serviceable item such as an air filter require nearly an hour to replace and possibly require a technician to do it. If a design concession was necessary for some reason that required moving the air filter from the engine compartment to under the dash then BMW should have at least done a better job easing the replacement process.