Most users don't use the "Advanced Data Protection" feature, as it's turned off by default.
Assuming you don't have it enabled, then nothing changes the way that your data is stored, it's encrypted in transit, but not encrypted when it's stored.
Apple offered "enhanced" encryption (ADP) which meant your data was stored encrypted, so they would be unable to share it with Police if ordered to do so by a court.
The Government have insisted that they must have access to encrypted data, Apple had two options.
A) Add a back door, so they could read your encrypted data, but that would risk a "bad actor" working it out.
B) Stop offering the ADP service.
They choose B, which is to my mind the sensible option.
Personally I think it shows Labour don't have the slightest idea what they are asking or doing.
This sends the message that it's not safe to store or manipulate any data in the U.K. The IT world is laughing its collective cock off.