my only advice is when playing Mageslayer, you need to find another sources of damage to deal with enemies’ you cant freeze or to finish off others got freeze lock. You can use Spectral Bludgeons + blue set for Trozan + MI offhand for more -CDR to Trozan and freeze them even more with nuke from TSS skill. Or use dual-wield build like this build.
or you can try something else on your own. My Spellbreaker use Northern Wyrm crossbow (the weapon got buff to VoS this 1.1.9.0 patch), and using 3 x BS + spam Chillspikes (mostly 85% pierce converted to cold) and aura passive damage from Veil of Shadow to deal damage (GT: https://www.grimtools.com/calc/a2dQGn5V). Freeze-lock bosses is a very fun gameplay style 