Most builds don't bother with freezing pinnacle bosses which, on top of the fairly high ailment threshold of 25m, have another 70% less damage taken mod that makes it pretty hard to freeze them. The ailment itself is still fairly useful if you can achieve it as it gives you -70% action speed (relevant thread) against monsters that 'Cannot be fully slowed' (aka most endgame bosses) but the payoff usually wasn't there because you could invest in more damage instead and just kill them faster. The reworked Heatshiver changes this though, as you now can in theory more than double your damage if you can reliably freeze everything.
This is one basic example on how to do it using Ice Trap Inquisitor on a limited budget. Ice Trap in particular is a good choice because the divergent version has a freeze multiplier. Also, realistically Inquis is the only choice at the low end as you need multi-element pen to properly utilize the extra fire damage. There are other ways to do it (which are most likely going to be omni setups) but this is the most straightforward way I found. Against uber bosses, this setup freezes bosses for around 1.4s, for normal pinnacle bosses about 4-4.5s. This value can be scaled at least twice as high, potentially even higher by filling in rares, woke gems, flasks and Ashes in particular.
https://pobb.in/LqweWjW45Jlm
https://preview.redd.it/z562pgo2eph91.png?width=740&format=png&auto=webp&s=c603ebc47d131343c2d26918c8d4fe80cd449aed
