If you duplicate your formula field and turn it to text, you can add text value in dynamic filter.
But you ca’t use formula field in filter (unless it’s primary, i guess, but not sure)
“At the moment, it is only possible to use a date or single-line text field when using the dynamic conditions option”.
that’s quite strange, i’m using simple automations to maintain links between tables in large bases, and often encounter such ‘limits of input data type’
you can use workarounds:
create additional text field, add ‘update record’ step 2, “construct” your value, using the same concatenation, in ‘step 3 - find records’ - use value from text field
create step 2 ‘run script’, define any variable name (‘var’ for example), insert value from formula field (and it allows you to do it … i don’t understand what’s the problem for airtables to let do the same in Dynamic filter for ‘Find records’)
script will consist from one line
then you can use this ‘anyLabel’ as input data for next step
I don’t know which is better, second lets you to avoid redundant field, but usually I’m trying to act without scripting, where it’s possible.