I can't opine on CR, because I pay very little attention to such things (and frankly, unless this is intended for publication, CR is mostly academic and you should focus more on how the monster you went to all the trouble of designing serves your specific encounter needs). Unlike some people I actually think you're doing alright in terms of the attacks, since, with the Legendary actions (once you get legendary resistance properly away on its own) he's making 5 attacks per round, each of which does an average 17 damage (if he hits, which if he's going reckless he mostly will). So while I think maybe you could up the damage of the hits a little, I'd be careful on that front. If you plan to play into the reckless attacks I might up damage by just expanding his crit range.
The first problem is in range and mobility. This fiend should probably fly, teleport, and/or have a ranged attack option. As is he will get locked down and never meaningfully threaten most of the party. A party member who goes toe-to-toe with him will feel how this is a major fight where this guy can easily do 75+ damage to them a round, but it might not feel impactful for other players, who get to stand back and just chip away at the guy.
The second problem is in vulnerability. In order to make this guy scary you're going to want to attack recklessly, but if all attacks against him are at advantage an AC 17 enemy with 205 hit points is going to be short work for an appropriately leveled party (that doesn't fail the fear effect). You want them to win, of course, but you want this guy to go three rounds with them at least, and as is we're talking three rounds at most, if he's fighting solo. If the party mostly beats him on initiative, passes their Wisdom saves, and just all out attacks, he might be lucky to make it through 2 rounds. I'm not usually an advocate of just throwing more meat on an enemy, but given the reckless attacking he probably needs another hundred hit points to reliably put up a good fight, or else he needs minions or something.
This guy will slice and dice anyone who goes toe to toe with him, but he needs the mobility and staying power to spread that pain around for a few rounds to really be a satisfying foe.