In order to squeeze out the most red crits possible, I recommend putting gladiator set mods on [Helios]' [Deconstructor] (since it can equip melee mods). Even if you unequip the sentinel you were using with it in favor of a beast companion, it remains as a hidden equip, allowing it to be used as a "stat stick" to get a huge amount of bonus CC.

This is something i'd recommend to accompany most melee builds right now, as there's virtually no downside to doing so and it comes as a huge boon.

Optional: If you have the mod space, try putting [Gladiator Aegis] on your warframe for just that little bit of extra crit chance. Plus, its more armor, so what's not to like?