Supply growth is not a bad thing for a crypto currency. Ideally the protocol rewards participants enough to incentivize them to secure the network, but no more.
You realize supply growth was significantly larger with PoW, right? It's like saying "Ethereum uses energy too!" completely ignoring the fact that it uses 99.9% less energy.
What has supply growth anything to do with how the network is secured (PoW specifically)? There is no correlation nor relation whatsoever between the two.
Ethereum lowered the issuance rate dramatically when it changed to PoS.
The reason it was able to do this without lowering the cost of a 51% attack is that it no longer has to rely on rewards alone. It can also apply penalties. Certain provable attacks result in automatic destruction of stake. In PoW terms, it's as if a 51% attack caused the attacker's mining rig to burn down.
Security is strongly correlated with issuance i.e. supply growth. If miners must spend X amount of value to compute hashes and secure the network, and the issuance or protocol reward is not sufficient to justify this spending, the security of the network is at risk.
As a percentage of supply, Ethereum only issues about 10% as much as Bitcoin.
On top of that, a portion of Ethereum fees are burned instead of paid to stakers. The supply is still slowly increasing, but at a (fairly modest) fee level of around 16 gwei the supply starts to shrink. The higher the demand for blockspace, the faster the supply shrinks.
Ethereum is leaky, too. Since the merge, supply has grown by more than 2500 ETH.