That is exactly the path I started down as well. Discovered I could split without a delimiter and it would split each character, but like you found out, apparently you can’t rollup an array. You can only rollup on rows. Same with the Joined List column. It only works with rows and not an array. I was attempting to do something with math to replace letters with ‘+1’ and create a dynamic math column of some sort, but I guess that’s not possible either. Did some googling and found a formula that works.
I agree, this would be so much easier with wildcards or regex in the template column. Building out all the replacements isn’t horrible, but you definitely wouldn’t want to do it multiple times. I agree, that (trim, substring, length, slice, etc) would help a lot here. I kept trying Len() or Length() in a math column in the hopes that maybe it existed, but we didn’t know about it.
All that math we learned in school, and subsequently forgot because we swore we would never use it in real life…does come into play sometimes. Here’s the info I found on the formula.