Davy Jones almost certainly was a more evil ruler of the world.
I wouldn’t be shocked if Imu and Joyboy were allies against him honestly.
I think alot has to do with longevity of the story.
For a good chunk of one piece story (15 years I guess) we had been fed this narrative that WG is true suppressor and evil while Ancient Kingdom was good - slavery, ohara incident, Ace execution, Robin's plot, cleansing and Reverie.
Oda fed this narrative for so long that WG came across as real big bad.
However, in recent times, we have seen hints which kind of goes against what we were being fed
1) Rayleigh who knows true history asked Robin to figure out history herself and perhaps she will reach to different conclusion than he did - the first major hint which reflected there's more to Ancient Kingdom lore than what we were being fed.
2) VP who did research on the history was conflicted about the history. VG lore came nearly decade after Rayleigh's hint and it double down on it.
In short, two people who knows true history had been portrayed to be conflicted about the ancient kingdom.
3) Entire Xebec flashback and Davy Jones plot hinted at Davy being the ruler of Ancient Kingdom which is in line with the conflicting opinions Rayleigh and VP has.
4) Lily's plot - Lily is the ancestor of Vivi and and one of 20 who allied with IMU against Ancient Kingdom. It's after formation of WG that she disappeared.
Considering how good Alabasta kingdom had been portrayed and how good vivi is, I feel it's safe to assume that Lily joined hands with IMU and remaining 18 kings against Ancient Kingdom because she felt AK's rule was bigger evil.
Infact, she perhaps felt to stay below and diverge from WG later when she realized that WG is creating a order of racial superiority of 20 families and not true government as she believed.
5) Hints of IMU and Joyboy being allies or friends
6) Xebec and BB - both having goal of King of the World - a status IMU has can't be just mere wishful thinking or coincidence unless Davy was the real king.
7) And, most importantly, slavery aside, WG actually is trying to establish a world order for 800 years. WG portrayal is more like far right elected government who wants nations to ally or affilate with them so they can have a world order with balance of power.
All of their acts so far has been centered around just two things
1) Maintain order
2)Suppress any information or event that can lead to Ancient Kingdom
Yet, they are clearly struggling in achieving them. And, more they struggled, more authoritarian in approach they became - more power they abused to force nations to go as per their world order and beliefs.
As I said earlier, WG is an organisation with good intentions but with bad means to achieve them.
Davy Jones seem like a bigger evil in the past who ruled Ancient Kingdom with iron fist and made entire world the enemy of the ancient kingdom- a true dictator kind of vibe (something I didn't feel seeing IMU at all)
Joyboy story of being the first pirate who sailed to seek freedom fits this narrative as well.