At freezing temperatures, regardless of relative humidity, the actual moisture content is very low. And then, chemical reactions just diminish to near zero anyway. Why frozen foods retain their fresh characteristics.
Me, I no longer worry about any of this. See my previous observations.
Paul let me state : There might be no need to freeze (developed) E6 Films = slides!
From my point there are archival recommandations with high tech climate control!
But listen : The general statement from professional archive personal is the following :
Color Films AND Prints are
Not archivable
!!!
That sounds not so fine to all of us! The difference is to bw films and prints
= more than 200years

!
So the point of that professional people with color archiving is the lost of colors
(All colors) in a period < 100 years

!
(70 - 90 years from my point)! But if you can't feel fine with color shifting you have to devide this period of massive lost very simple with 2 - 3! = 20 - 30 years!
So we are generally save from (visible shifts) for a guaranteed period of 10 years with Velvia
films (same is with Ektachrome)!
Listen - this 10 years period is in regards of "bad" storage!!!! The rest is dependable from
individual storage conditions and your personal feeling with smal shiftings!
If you (or I am) would feel fine with colors of E6 we both (perhaps) can easily imagine that
PE for example would not be amused about same conditioned colors

!
So it is dependable from different "views"!
Let us count in these 10 years of absolute safety (PE would also feel confortable) caused from
NO SHIFTS AT ALL - then you can multiplicate this time with normal and best storage condition
for sure with factor 2 and factor 3 !
That would answer OP's question a bit (because there is no general rule at all)
Kodak gave E6 films > 160 years (with projection intervall) and 200years stored in total darkness!
But this is not our workflow and illusion!
Beside NASA can prove it

! (with 100.000,- USD climatic control per years)
From my point you are save for 25years with E6 and I can live with very small shifts after 35years!!!
And let me state : I am such a louser from storage E6 slides



!
So I can not remember color shifts with slides from the 80s

!
with regards
PS : Don't freeze slides, don't let slides sleep in vacoom = don't sent slides to ISS!