The priority fee (miner tip) comes from users, so it's not inflationary. For the block to be deflationary to the ETH total supply, the base fee (also comes from users), which is the only part of the fees that is burned, must be higher than the 2 ETH block reward that comes from inflating the ETH total supply.

There is also ETH supply inflation created on the POS ETH beacon chain which is not being included in the total supply until the POW to POS merge. EIP 1559 basically just slows down the rate of inflation by burning the base fee portion of the network fees instead of rewarding it to miners.

https://www.youtube.com/watch?v=faf1M4fzv8I