I'm shocked they named the movie Gladiator 2!
Normally a sequel comes out after many many many years (for Gladiator that is 24 years!), the studios wouldn't put a number on the title but a secondary title like Beverly Hills Cop: Axel F, Top Gun: Maverick, Bad Boys for Life.
The reason for the omission of numbers is the studios are afraid the young audience (which is the most important demographic in terms of box office) would think "I didn't watch the previous one, I'll skip this one." So they attempted to imply "This is a completely new movie, you don't need to watch previous movies."
Does any sequel released many years after the previous one like Gladiator use a number in the title?