So, not quite deflationary but pretty close. If Ethereum network usage picks up again like it did in 2021, Ethereum will experience long stretches of time where it is deflationary.
PoS issuance rewards are 4.6%/year, which can be offset with burn rate, but it is at 0.5% now.
The site projects that in 200 years, burn and issuance will be at equilibrium.
PoS issuance is 4.6%/year per staked ETH.
Only 14M of the total 120M ETH are staked right now, making the real issuance only 0.5%/year when taken as a percentage of total ETH supply.
Subtract the 0.5% burn rate from that 0.5% real issuance rate (with rounding errors), and that's how you get Ethereum's current situation of being "pretty close" to deflationary.
Will gas fees burn or go to stakers?
EIP-1559 is the Ethereum patch that introduced the fee burn in Aug 2021.
It's a bit complex, but basically speaking, the higher demand is for the network, the more expensive transactions become and the more ETH gets burned.