I keep seeing people referring to any of these changes as being "large-scale." But they don't have to be.
It wouldn't be too hard to switch most (though not all) short-rest-based resources to being long-rest-based ones. Those that can only be used once a day (like Arcane Recovery) are probably fine, because most groups do take at least one short rest a day. Channel Divinity and many things of its nature are fine too.
The two main sticking points are going to be Warlocks and Battle Masters. The Warlock is deeply tied to the short-rest system, and I don't see a simple way forward to fix that without...making it just another caster. Perhaps they could have a certain number of daily "recharge all slots" benefits? Unclear on that one. Battle Masters have a different problem: giving them an appropriate number of maneuvers so they don't flare out at the start of the day and then have nothing in the tank, without it seeming (to reference back to Osgood's post) like "two breaks and a lunch" type mandated limits. One option would be to give fewer dice but to grant all of them when rolling initiative, e.g. perhaps "you get a number of Expertise Dice equal to your Proficiency bonus at the start of each combat." That's still not going to quite match things (it would advance more slowly but likely give more total dice), so again I'm not comfortable just emphatically endorsing it.
Apart from those two things though, switching most classes to the "PB per day" rather than "X per short rest" system would solve many of the problems without requiring any meaningful change to the overall system. It would even still be compatible with the "original 5e" versions, since ultimately the two should end up in essentially the same place, just one is more front-loaded than the other.