So what if we go basic, numbers for letters and see if there’s any patterns?
OBKR
UOXOGHULBSOLIFBBWFLRVQQPRNGKSSO
TWTQSJQSSEKZZWATJKLUDIAWINFBNYP
VTTMZFPKWGDKZXTJCDIGKUHUAUEKCAR
Becomes:
1521118
21152415782112219151296222361218221717161814711191915
202320171910171919511262623120101112214912391462142516
22202013266161123741126242010349711218211215113118
Reversing it:
AEUKH or AEBAAAH or OBAKH
Or gibberish, gibberish, gibberish

It seems like the letters-to-numbers conversion is kind of like multiplying by 1. It doesn’t seem to do much of anything, does it?
Could there be some formula that we’re supposed to apply to the numbers which would then give the correct plaintext?
Yeah, it’s possible. Unfortunately we don’t have any idea of what type of equation they might have used so it would be all guesswork at this point in time.