Hopefully it won't be long before modders fix this and add in requirements for multiclassing and bring the pre-Tasha's Cauldron stats back.
Why would it need to be modded out?
We can simply choose to put 13s in the classes we are multi-classing into.
Nothing is stopping us from adhering to the D&D rules.
I maybe wrong, wouldn't be the first time. If we are only getting +1 +2
Then my Shield dwarf loses a +1 which could be the difference of getting me to 20 in a stat, which is big. And assuming the rest of the points we get to aliquot
are the same Ill have no way of making that +1 up.