merc resistances

hi
how much fire resistance do i need for my merc using enmitys embrace?
is there a cap or is it just the more the better? how much penetration can i rly get? or how does it work?
thanx

(Apologies, I did not realize this was in the POE2 section and thus the information may not be completely relevant, as I was answering based on POE1. If the question relates to Early access there may be mechanics I am not aware of, but I thought I had clicked on the thread in the POE1 gameplay help and discussion section. Did it get moved here? I cant see the ring listed as a unique on the POE2 wiki. Maybe is possible that is was moved in error since there is a lot of POE2 threads in gameplay needing to be moved.)

There is some information on the wiki, looks like the numbers go pretty big.

https://www.poewiki.net/wiki/Enmity%27s_Embrace

I would assume there is a point where it no longer becomes feasible or efficient to get more, unless you are in standard where that broken fire res armour exists that gives 24k fire res.

Beyond using that, I would think it is pretty difficult to reach 500 or 800 overcapped to reach the 200max. There will be some diminishing returns as well. Each point towards reaching that 200 will give you less value than the last. It seems like just more is better in general though. I assume there is breakpoints as well, that require a certain amount to get to the next integer of penetration, depending on the rolls on your ring.

ty