No one knows. The inflation rate will start becoming pretty irrelevant by abount 2027 looking at the charts, so inflation will not be a big cause of lack of stability (by behaving like fiat, im assuming you are talking about this and nothing something else).
Once and if Bitcoin stops at a certain price, and if the adoption is near mainstream levels, it will be at a price a lot times higher than the last ATH. Simple supply and demand dynamics. This includes prices like 100k to 1 million dollars, but we see this as insane now.
It was insane for a very early adopters to get to $1 and it got there. After the same for $100 and $1000, and Bitcoin again got there. So I wouldn't bet against anything anymore.
Also we cannot compare Bitcoin to the Fiat. Bitcoin is much more than just a currency. It's also a commodity, a store of value and just a tool for different reasons. I mean people got married and officiated this using the blockchain.