A stable currency would have an inflation rate of 0%. Inflation does not cause currency stability, it decreases the value of the currency.
By definition, its value is changing.
Sure, and if the government had centralized control of all prices, it could mandate that. Since it doesn't (even those that assert that power don't have it in practice), what it seeks to do, as far as stability, is try to acheive low short-term price volatility, and as it turns out, experience shows that low-to-moderate inflation helps with that.
The M1 isn't the measure that matters - but it is a fact that large amounts of money are appearing from somewhere and that is probably the most significant factor in the currency losing value. Price controls are an overreaction, there are easier ways to make the currency more stable.
[0] https://tradingeconomics.com/united-states/money-supply-m1
No it doesn't. M1 also includes demand deposit accounts (checking and savings accounts), among other things that aren't physical currency.
The USD is one of the most stable currencies in the world.