Does anybody know if it's possible to move a line level field that was added via UE beforeLoad on the form? It's being added as a last column and I need it as a first column.

In general I don't think adding fields on beforeLoad is a good practice because there is many limitations with those, unless there is a very specific reason to add them only on beforeLoad you should avoid that. I'm not aware of any line fields moving methods in general(not only the ones added beforeLoad).

We tried doing this but we weren't lucky. We just added a custom field and moved it via form customization instead, then manipulated the logic via script.