I would argue all currencies are unreliable ,because they go down in value due increase of supply. Throwing 2-4% every year sounds awful
Yes, the causality of "create too much money -> inflation" is plausible (but note the emphasis on "too much").
However, we live in a world of endogenous money, where money is largely created by commercial banks in the form of loans to private entities. When prices increase, those loans get bigger. So there is also the causality "inflation -> create more money".
At the same time, there are other factors that can drive inflation, such as workers and companies exercising price setting power (which Econ 101 likes to pretend doesn't exist, but plays an important role in the real world).
So yeah, the causality that you're casually throwing out there hasn't actually been proven as the driving factor here.
At the same time, the widespread belief in it and similar misunderstandings causes us as a society to make extremely damaging macroeconomic policy decisions, in particular the decision to attempt to fight recessions using monetary policy instead of fiscal policy.
We had 4 years with 4x the reward, 4 years with 2x the reward, and about 3 years with the current reward, which makes for 1/(4x4+4x2+3) = 1/27 inflation.