Assuming you get one Apocalypse Heart per Expert run on average: 5+20+45+65+80 = 215 runs needed for just hearts. 215 runs * 30 AP each = 6450 AP needed. One gets 1 AP every 3 min so 6450*3 = 19350 minutes of natural AP regen required to get all copies of the summon from the shop. 19350 min/60 min per hour = 322.5 hours. 322.5 hours/24 hours per day = 13.4375 days.
Meaning, it's literally impossible to get a maxed out summon from the shop alone, unless you get at least one as a drop. Even with one drop, it's still 8.4375 days of making sure you never waste any AP. We only have 1 week, but surely you will level up/use potions over the course of the week so it can be considered that you'll make it as long as you get one drop.
Again, this is assuming you get at 1 heart per Expert run on average. If you are even unluckier then RIP.