Check out diminishing returns on MF after a certain point. I wouldn’t say go 0 MF but around 250 you’re probably good to go.
Also, boss TZs always give me something cool eventually , but honestly it’s all RNG, chaos monsters have the same drop table as a TZ monster so you’re not changing the drop tables or the drop rate. 250 mf + clearspeed is what I’d be after. Then farm where you enjoy where the drop table is the best for what you’re looking for. Google monster i levels at what areas for more specific data bc i can’t remember that
Lieutenants and Dia himself dont have the same drop table as a TZ monster. They cant drop most of the TC87 items such as Tyraels.
And TZ monster have way better odds at the higher TC items than their non TZ version, even if this non TZ version can spawn the item it is still better to hit TZ than normal version, if you speak odds wise.