Blues Brothers 2000 is a fever dream Elwood is having.
The events of the movie are completely nonsensical, even for a Blues Brothers film. Zombies, a voodoo priestess, driving a car underwater and surviving? All of it is just a really confusing fever dream Elwood is having while in prison.- A darker variant: It's Jake's Dying Dream.
The events of Blues Brothers 2000 are shown through Elwood's eyes during a mental breakdown.
Everything up to the point he finds out everything he went through in the first movie was completely in vain actually happened. After learning about losing his brother, his father figure, and everything he worked for all in the space of a few hours (minutes?), everything we see is only from Elwood's point of view. In reality, he was undergoing severe Sanity Slippage and kidnapped Buster, Mack, and the other members of the band against their will. The scene where the Bluesmobile drives through a loop-the-loop while on fire was just a minor engine fire, the fair concert where the band plays "Ghost Riders in the Sky" to hundreds, if not thousands, was in fact a small bar with maybe 10 people in attendance, and the scene where they drive through a river with an explosive boat on top was just the car careening into a small creek and gently bumping an old man's fishing boat. What we see is Elwood slowly losing his mind and imagining things as either much more or much less mundane than they actually are. The God in the Blues Brothers Universe is a stubborn fanboy of theirs.
He had the orphanage in danger, he obviously inspired Jake to bring the band back and almost every thing that woulda been physically impossible in real life was the result of his intervention. When they put on the one good concert, he rewarded them with their oprphanage saved at the cost of them going to jail. In the Sequel, God was bored and wanted to do it again, but then realized "I'm god I don't need an excuse I'll just do it." Hence why there was no legit reason for Elwood to do it again.