I thought the NWA's Lucky 7 concept, minus the fact that draws counted as wins and the 6:05 time limit, would be great for the TNT belt, and a way to get around Cody's stip if needbe.
How I'd do it, perhaps after Cody loses it:
Every week , folks interested in the shot enter their names, a name is drawn from the hat (can still be someone "not in AEW" if you want to debut someone)
That person gets announced on Dark, the match is on Dynamite
20 min time limit, you win, it's 1 notch towards 7.
You draw, no time limit rematch to open the show the following week.
You get 7 wins, you get to automatically face the champ the next opportunity that's avaliable and you vacate the title (so if the champ has a match scheduled the following week, you get it the week after, though you still vacate the belt)
A vacated belt is decided in a battle royal the following week.