What would you do if you  had  God's power for two weeks?

I think this is blasphemy.

God can give power to his faithful believers for useful purposes, well, the believer always asks God how to use his power for the purposes of his will.

Now, relax!?

Make sure every person had at least one meal a day.

Undoubtedly mess it up.    So be pleased it is just fantasy

Prove Islam is Fake Prove the Roman Catholic Church is Fake

Let the South win the Civil war Make sure that Nukes never worked

Hitler St6alin and Mo would not be Born

the USA will lose the War of Independence

Prevent WW1

There is something called Oobleck, a non-newtonian fluid. That is, it acts like a liquid when being poured, but like a solid when a force is acting on it.

So, I would create something similar that seems to be a chocolate marshmallow -- you can eat it and it would seem to be that.  But I would replace the exterior walls of all churches with this material, and it would be strong enough to support the church -- just like the original walls.  But anyone, using just the strength of the fingers, could pull off a piece to eat.

And, of course, if enough people do that, the church would eventually collapse.

Since divine knowledge and understanding are part of his power, I would probably do exactly what God is doing now. If perfection alters it's course, it ceases to be perfection. 

You’d have to specify which god and the power. I still have human flaws. If I could use it to do good, why doesn’t that god do the same?

Tough call. I'd start by dropping the CO2 levels in the atmosphere by about 150 parts per million, and lower it's concentration in seawater down to the levels when atmospheric CO2 was at that lower level, as well as getting rid of excess heat in the biosphere back down to the levels of 1800.

That would ease much of the climate change issues of our time.

Next, I'd mutate Covid 19 into a totally benign virus.

Then, I'd hack the finances of every billionaire and drop then down to multi millionaire levels, with the money so liberated going to all the minimum wage workers.

Next, let's give animals guns to shoot back at hunters and poachers. Whales all get torpedoes to fire at illegal whaling ships.

And, an eagle grabs Donald Trump and flies him off, never to be seen again. Then, at Mitch McConnell's house, a fissure opens up right beneath him, and he's never seen again, either.

Similar stuff for Putin, Boris Johnson, Xi Jinping, the whole Kim family in North Korea, and definitely Bolsonaro in Brazil and Erdogan in Turkey, and Assad in Syria gets dropped into a live volcano.

Oh, and all major churches go bankrupt.

What I would end up doing is screwing up the universe until the end of time. I'm not qualified to wield that much power, but that much power would be so attractive, I don't see that I'd be able to keep myself from using it, and using it at all, that'd be like putting a three-year-old behind the wheel of the family SUV barreling down the interstate at 70 miles per hour, saying, "You drive wherever you want for the next two weeks," and then letting go of the wheel, so, basically, I'd end up crashing the universe and destroying everyone and everything until the end of time, which would be by my actions brought way, way, way forward to some point within those two weeks and probably early on in them.