I would jump up and down with GM on this. $44/day for a rental.....what a joke. If they can't build a quality vehicle, then they should at least let you drive the equivalent size vehicle while yours is being fixed.
There are many posts here about the 2021 and newer engine dilemmas and their outcomes. If you want to keep the vehicle, demand and extended warranty! If you don't feel good about it now, you could pursue a buyback and see where that gets you. Then you could buy a Honda or Toyota (I've been GM loyal my whole life, but my views have been changing based on their chitty quality and high prices, so I don't blame anyone for voting differently with their money).
My dealer agrees that the $44 a day policy is ridiculous. Luckily they escalated and I now have a Suburban loaner until my Tahoe gets fixed. Also, I already purchased an extended warranty for 7 years are you suggesting I should ask for more?
My biggest fear is that the new engine could also have issues. Has anyone had that happen where the engine goes out more than once?