I wonder what the power level of a 10th+ level feat looks like let alone a 20th. I mean lucky is one of the top 5 feats now and this didn't do much to depower it.
In fact a 17th level character with the right ion stone can have 7pt of luck with a 1st level feat
If 1DND keeps the same pattern it's a level8 or 12 feat.
For magic,that's 4th level magic and 6th level magic respectively.
For martials, it's trickier
8th level is between your 5th level power spike and your 11th level power spike.
A barbarian gets Feral Instinct at 7 and Brutal Critical at 9.
Monk? Evasion and Stillness at 7. Then their movement improves at 9
Rogue? Evasion at 7 then a noncombat Subclass thing at 9
So a 8th level feat should be about the power level as Evasion.
12th level power is trickier as you just got a
huge power spike at level 11 AND it will be your first feat if you maxxed out to 20 first OR your first or Second ASI if you went down a 2 or 3 feat tree.