I think they wanted to see if they could still get fastest lap if they put Tsunoda on softs. Since Ricciardo couldn’t get points anyways, they used him to test that idea out and then have Tsunoda go on softs as well to get the point. If Ricciardo couldn’t do it, it wouldn’t be worth the risk to try it with Tsunoda.
Why did they pit him for softs with so much left in the race?
I think they wanted to see if they could still get fastest lap if they put Tsunoda on softs. Since Ricciardo couldn’t get points anyways, they used him to test that idea out and then have Tsunoda go on softs as well to get the point. If Ricciardo couldn’t do it, it wouldn’t be worth the risk to try it with Tsunoda.
I doubt anyone even works for AT anymore, it’s been a while since I’ve seen their garage or pitwall