Peak Sergachyov has shown a level Chychrun will never attain. I think by the end of 2022-23, he was pushing Hedman (albeit an aging Hedman) as the best defenseman on the Lightning.
Needless to say, 23-24 was not the kind of follow up season hoped for - I had expectations he might establish himself as a true star #1, best defenseman on a contender type season. Needless to say…it was not that and then he missed most of the season.
But still easily take him over Chychrun - I think the waves are just a higher level even if the similarities of peaks and valleys are there.