I'd still extend Keller in a heartbeat. There's no denying that he's started to trend down and some of the doubts people (often in fantasy baseball circles) raised about the K limitations have come to light. I wanted to write off the light-hitting Guardians teeing off against him to post-ASB break inconsistency, and he seemed to be headed towards a rectification of the game yesterday before essentially being the reason that we lost, but the overall trend has been down.
Still, starting pitching is extremely scarce, and you just can't fabricate even mediocre MLB innings out of thin air. If he builds up to 185-190 innings, you absolutely bank that and the improvements he's shown for next season, and I would say that extending him is still one of the higher priority things that need to happen. Even as a 4 ERA pitcher, he's plenty valuable to anchor the rotation that needs further built out with him in it. He's just 27 and starting to put together the tools, which is not uncommon at all for MLB SP.
I think Hayes is the more extreme (but risky) example, but trading him just has "will further break out elsewhere" written all over it. You can say the same thing about Bednar, but trading your main young pitcher right now would be waiving the white flag and signaling that you don't want to seriously compete until 2026 or 2027. I don't care how good Paul Skenes is, or how nice Jared Jones' slider/cutter is, any kind of immediate progression in the next few years requires Keller in the mix, and the expectation should be to extend him and add further to the payroll in free agency or otherwise.
With Bednar, there's more volatility for the closer position, but it all depends on the return. Gun to my head and I'd probably take a shot if it was top-100 talent and other pieces who would factor in pretty immediately, but it feels like the right move is to just play it out with him.