Lord of The Coast was easily Tiger Level, i can find Dozens & Dozens of Characters who are way Stronger, that Chapter 1 Luffy can One-Shot,
Luffy's Feats of Strength alone would put him at Demon Level, adding his Rubber Power & Fighting-Style, He would be considered Dragon Threat just like Garou was at Start of Monster Raid
Now add Post-TS Buff + Haki + Gears (Up until 5),
Dragon Level would Threaten No Top Tier
Just Kuma for example could easily take down Multiple Dragon Level Monsters,
It's at Dragon+ that things start getting Debatable,
Garp would eat Dragon Threats like Marugori for Breakfast