The fact that the overall amount of money is limited makes btc resistant to inflation. However, only ne type of inflation can be avoided with this feature. Btc is prone to some other types of inflation, first of all, there is a risk that some whales will turn into "global banks", which would regulate the value of btc. The amount of crypto collected by whales can be so large that a small group of whales would have much more money than the rest of the world... Thats exactly what we can see in dollar financial system now: global banks and richest tycoons are able to control inflation rate just by managing their assets, in this case the overall money amount remains the same, while fiat money values can change dramatically.
But the decentralized nature of Bitcoin provides a layer of protection against this. Control isnt centralised like in standard banking systems. Even though whales have a lot of money, the real power is still with the community, with users like you and me. There is a real risk that a few people will gain too much power and control Bitcoin, but its important to stay true to the decentralisation principles that Bitcoin was created on.