https://www.youtube.com/watch?v=DX73uXs3xGU
https://www.youtube.com/watch?v=YAneTFiz5WU
As far as cleaning, AK, like many guns of that era, carries its own cleaning & maintenance toolkit inside the gun. Although it is a bit unusual in that regard in that this kit is, in fact, sufficient to remove any part of the gun that is not permanently attached. Which is to say, AK can be serviced in the field, without an armory, to a greater extent than most other options.
But the main reason why it's so popular isn't so much because of any of that, but rather because it's very cheap to produce at scale, and China especially has been producing millions of AKs specifically to dump them in Africa, Middle East etc. But where large quantities of other firearms are available for whatever reason, you see them used just as much - e.g. Taliban has been rocking a lot of M4 and M16 since US left a lot of stocks behind.
And Western supplies are mostly 5.56 for obvious reasons, although there are some exceptions - mostly countries that have switched fairly late and still have substantial stocks of 5.45, such as Bulgaria. But those are also limited in quantity.
So in practice it's not quite so simple, and Ukraine seems to be aiming for 5.56 as their primary cartridge long-term, specifically so that it's easier for Western countries to supply them with guns and ammo.
Soldiering isn’t sexy, it’s digging trenches, cleaning kit, and eating concussive blasts waiting to fight or die.
You don’t sit in a bunker all day waiting to defend a trench and not clean your gun.
The ak-47 famously only needs the first item in that list.
That being the key to its popularity.