I think the Ireland performance is being over praised. They weren't technically better, better organised or more effective than Scotland. They got a scrappy goal after sloppy Scotland play handed them a counter attacking opportunity and a corner. They had a second similar counter at 1-1 and couldn't score. Other than that they created next to nothing despite all that pace they supposedly had.
Scotland dominated the ball, particularly in the last hour. They created enough chances to win and more besides. They also played a game a few days previous while Ireland were getting massages and resting up.
I don't think you can ask Che Adams to do what he did against Ukraine three times in a week so it made sense to go with Dykes for this one.