Battery

eleonoraa ~ No, it's not normal. ...Does your iPhone 7 still have its original battery?

And what's the Maximum Capacity % here?...

Settings > Battery > Battery Health

Follow these tips to maximize battery performance and help extend battery lifespan.

õ¿õ¬

eleonoraa wrote: "Also, is it possible they might’ve changed the battery?"

The 100% capacity implies that, yes, they changed the battery. And the poor performance implies it was done by an unqualified technician and/or used a non-genuine iPhone battery:

About genuine iPhone batteries

...So demand your money back and buy a more recent iPhone model from a different reputable source. Older models such as iPhone 7 will likely soon cease to be eligible for future iOS upgrades such as next year's iOS 16.

õ¿õ¬

eleonoraa wrote: "I think it’s the original one."

So you bought a used iPhone 7, correct? ...From a reputable source?

When did you buy it and has the battery always been behaving strangely?

100% capacity doesn't sound right for a five year-old iPhone 7.

õ¿õ¬

There is no way an original battery in a 5 year old iPhone can possibly have 100% battery health.