Simple things require very little focus/time
So magic can be used to improve technology. To make and use a research laboratory on any science topic is really easier than in your world than in our.
Some are better at it than others
I think this is a key point. The weakest men and women would feel useless if they cannot try something else than magic.
So I think they would be the best engineers/scientists, eager to prove their values. They would use their little power to increase their potential and making experiences to make technology progress.
Spells require energy and mental focus
... Where technology doesn't. Take one of the technology improvement that ended the middle age: navigation. If I understand your world, magic can be used to cross large water bodies. But to travel - and transport commodities - through oceans is not at all a "simple things", so if it is possible, it would be only by the magic masters of your world.
On the opposite, a caravel made by engineers (who, once again, could have used magic to make it) would be able to travel as many times as it want with less energy. And on board, sailors can use their own power to make the ship travel faster, or the travel itself more comfortable by making food appear, etc.
So finally, I think magic and technology can help each other to progress. They are complementary, as technology is longer to prepare for usage but magic is an energy eater.
So yes, technology and science shall evolve to modern standards, and probably further.