I play the "upgrade hospitals to max before conquering endgame" gameplay too :)
Like, it is idle, I finish ~300 ap maps in 14 days, usually on day 8-10 I have maxed hospitals :D

@dangermouse

It's much faster to complete the levels after you ascended (i.e. finished all levels) due to the higher AP you got thus far.

But it doesn't necessarily have to be a hospital strategy to complete the levels quickly. I mainly rely on mercs strategy (additional mercs AP and mercs discount AP & artifact) in combination with bonus money boost, which also enabled me to finish OVN in a bit less than 4 days (i.e. MUCH faster than on the first run)

Edited 12/17/2020 21:45:48

In that case, what does your AP investment look like?

@dangermouse

107,5% additional mercs
50% mercs discount (maxed)

Plus ofc joint strike (maxed) and idle time (6h)

Increased ore/alloy sell values & increased money/resource caches are also useful AP at a later stage cause they are relatively cheap and provide more money for buying mercs

I also have increased army camp production and auto conquer/auto upgrade camps but they provide very little value except for the challenges