I've never been a fan of these ultra long term deals and think teams are generally better off trying to avoid them if their goal is to be a contender every year. You are almost guaranteed to eat some dead money and cbt space on the back end of the deals, and money can usually be smarter spent elsewhere.
There is another downside of signing these guys so young. A guy like Tatis hadn't even played a full season worth of games when he signed his 340 million guaranteed deal. If he was still going through his player controlled contracts would he be riding motorcycles, taking steroids (or making whatever mistake he claimed) and doing whatever else reckless stuff he was doing? Maybe he would, and some guys just can't help making the bad choices. But I have to think he would have probably turned out better if he spent a few years learning to be a professional athlete and adult and earning that big contract instead of being handed it as a 20 year old. You give a dozen 20 year olds 340 million and I bet about half of them will have their life go sideways and a good chunk aren't going to be motivated to put in the work it takes to be a perennial all star that is expected for that kind of money.