Will Apple's flat-panel ipad battery health slow down if it is less than 80%?

I believe it will.

The speed will definitely be affected, and 80% of them are already in a state of maintenance, and batteries need to be repaired or replaced. Battery health means that with the use of iPad, the maximum capacity of the battery will gradually decrease. If the battery capacity is less than 80%, the iPad's processor will be down-frequency, and the direct impact is stuck.