Depends on how it's done. Dekus entire character arc has been built around being the greatest hero and how he will literally sacrifice himself in order to save people. We even saw him freak out still trying to save people when danger sense first started to activate during the war, Deku is completely a self-destructive personality because he sacrifices his body for the good of others. We've been shown this multiple times throughout the entire manga, not only that, but we have been shown this trait of Dekus through other villains as well building up to this.
This isn't a surprising fact, as it's been hinted, teased, and lead up to practically the entire manga just based off solely looking at Dekus personality. Wanting to save someone though and successfully saving someone are two drastically different things, and just because Deku wants to save him, that doesn't mean he's going to be saved. Deku even states the only reason he fought other villains was because they didn't initially first back down, and we've seen him try to de-escalate things first before jumping into a full on fight with villains. His character has never been beat the crap out of villains, he wants to save people, he wants to save everyone. He is a self-sacrificial character, which is further shown off of him distancing himself from all of his friends who would stand by him just so they didn't get involved.
Deku has always wanted to try and resolve things without having to fight, and we even see special emphasis on Gentle Criminal, showing he still feels remorseful things couldn't have ended differently during that time. So yes, I do like that Deku is still trying to save people. If he suddenly wanted to try killing people his character would be doing a complete 180, and that's not how his character has been written nor developed. He's been written as a character that wants to save everyone, but just because he wants to save Shigaraki, doesn't mean Shigaraki is going to let him or be able to be saved. Like, this series isn't going to end with Deku stopping AFO, shaking Shigarakis hand, and them being best buds at the end of this.
Can Shigaraki be redeemed, possibly, it depends on how Horikoshi does the writing, but to me I don't see Shigaraki being redeemed. So I am fine with Deku trying to, but it's not going to work and I think that's an important distinction to keep in mind. Just because someone wants to do something, doesn't mean it's going to work out how they expect. Shigaraki has gone on a rampage and destroyed so much, that even if Deku stops AFO and Shigaraki has a "change of heart" nothing is going to change Shigarakis final outcome which from what I am thinking, is going to end up being death, in order to try and give us a "tragic" villain story.