Looking more closely at his last 3 year numbers in Japan, especially his K/BB rate, which is the one thing better than Yamo's, last year.
Imanaga's numbers...
ERA (IP) K/BB
2.83 (149) 4.4 in '21
2.04 (159) 4.7 in '22
2.66 (159) 7.9 in '23 (age 29)
Yamo...
1.39 (194) 5.2 in '21
1.68 (193) 4.9 in '22
1.16 (171) 6.3 in '23 (age 24)
I'm not trying to say he's better than Yamo, but if we are anointing Yamo king, based on his numbers, then Imanaga's look pretty good, too. Maybe not as good as Monty or Snell, but possibly close enough to be in the same tier.
At worst, he might be the best of the next tier.