I will readily admit that an AK is my first choice for a battle rifle, and here are my thoughts on your question ( as well as some extra thoughts thrown in )
I struggled with the lack of a BHO on a battle rifle as well, and this was largely due to me starting my real weaponcraft as a 17 year old 11B, and learning that the BHO was the indicator to reload.
I found that in true practice however, when frolicking upon the 2 way range, if I had a moment to think to myself " I wonder how many bullets I have left in this mag " then my next step was to take that mag out ( stow it if I thought to, drop it if I didn't ), and load a fresh one in. This way the answer was 30.
If you are engaged, you will seek cover naturally ( or you will get shot ). If you suffer a weapon malfunction, transition to your pistol to keep a weapon in the fight, and then get behind cover and go to corrective action ( HK users treat an empty mag as a malfunction, and the corrective action for an empty mag is the same as a jam on an MP5 )
If you have been in an engagement and are preparing to make a "big" move from cover ( forward or backward ) ) you want to do it with as many bullets at the ready as possible, so a reload is probably in order anyway.
All AK shooters are aware that there is a (small) possibility you will go to engage and get a click ( this also applies to MP5s, P90s, pump action shotguns, and many other popular combat long guns )... just like all rifle shooters are aware that there is a (small) possibility that you will go to engage and get a light strike, misfire, squib, or other terrifying "clunk" when you were expecting a triumphant BANG.
So just like you prepare for malfunctions by drilling corrective action till it hurts... Practice emergency reloads too. You may surprise yourself how quickly you will get your weapon back into service if you do it enough times, even under stress.
Lastly, on the note of the emergency reload where you use a mag to activate the release: I've tried it, got quick with it, and if YOU swear by it I will give you a high five because of your confidence. I personally have found that it is no faster than using your support hand to ensure that mag comes out, and I prefer not to fill my hand with something when I may still need the use of my fingers.
With the support hand method you are gripping the mag and activating the release at the same time, and I have never failed to successfully extract the mag this way ( watch me say never and it will happen tomorrow ).
With the fresh mag activation method, there is a microsecond where you are racing the depressed mag latch and trying to get the empty mag out before the catch re-seats behind the mag lip ( this is where the rake, raKE, RAKE!!!! HA! GOT IT THAT TIME! ) comes from.
Lastly, hopefully if you are in a gunfight, you brought friends... lots of em. And hopefully they have rifles too. If during an engagement, you all go dry at the same time... you were never meant to win that battle... sorry.
If this was a helpful I'm glad, and if it was a waste of your time I apologize.