Maybe give untis in an officer Korps, these Korps will not directly count for health. So an infrantry unit dies, the health goes to zero but the officerkorps stay maybe at 6/10 so the unit disapiers from the battlefield but ce be reinstated with the expierienced officerkorps keeping more Expierience intact.
For tanks the healt could be the tanks while the crews would be like the officers for infantry, all tanks get destroyed but you can rebuild the unit with the leftover crews.
For planes it would be pilots and that makes sense to simulate parachuting and crash landing.
–> this would simulate something between a supression and a kill.
For artillery this could simulate a withdraw were all the guns are left behind, or a forced retreat where some guns are left behind so you have more guncrews than guns , simulating a hasty reatred or attrition inside a kessel/ cauldron were losse in heavy equipment can not be replaced.