Pandora was over $500 million. SWGE has quick and table service dining.Pandora alone cost at least $500 million. One restaurant, 2 rides, some nice theme work in a few acres. All rest of the park infrastructure was already there. Parking lots, ticket booths, entrance and exits, restaurants, souvenir shops, transit, etc. Estimate for SW:GE is about $1B. Again, 2 rides, one quick serve and some very nice theme work.
Maybe you get away with $5-10B if you build something like DHS or AK at opening. Skimping on the rides saves more money than skimping on theme. Animal Kingdom, which opened with just a few rides and basically a lot of theme work, cost $1B 20 years ago. That's at least $1.5B today. EPCOT was around $1B in 1983, that's over $2.5B today. Expedition Everest alone was $100 million 15 years ago.
I'm probably high on that $15-$20B, but a decent, immersive, modern Park from scratch to compete in Orlando? Easily $5-$10B. You need 2 or 3 SW/Pandora type areas. Probably 2 or 3 more TSL or NFL type areas. Parking, transit, entrance work, a few nice restaurants. It adds up quick.
Shanghai was a $6 billion park.