inflation was exported and spread out throughout the world
Yes, I think this exporting of dollars has been a big contributor to the massive decline in monetary velocity over time.
Ethereum doesn't have a maximum cap on its coins
That's correct. Notice that I said "Burned transaction fees could result in a decrease in Ethereum’s monetary base" instead of "Burned transaction fees will result in a decrease in Ethereum’s monetary base". There would only be a decrease in Ethereum's monetary base during periods where burned transaction fees more than offset the issuance. Under Proof of Work, those periods are rare, under Proof of Stake they could become much more common.
BTC can't be inflated to zero
BTC also has steady inflation; it is only considered deflation relative to other currencies that all have higher deflation rates. (It is possible, but unlikely, that the ongoing 'loss' of BTC due to poor key storage is already greater than its inflation rate. If so, then BTC is technically deflationary.)
Don't get me wrong, I like Bitcoin and I hold BTC in my portfolio, but potential investments should always be considered relative to your other opportunities. A maximalist position is intellectually weak, unless it is constantly reexamined in light of other narratives and new information.