Connect or forge for fields validations

Hello community,
we are using Jira cloud in my company. In the create issue tab, i would like to add a condition over two fields making them dependent on each other with defined rules : for instance i have field1 and field2, i want something like this : field1 = SomeCountry → field2 = [options Based on that country]
Since cascading fields can’t be shown in Timesheets reports, i’m trying to develop a jira App that will do this. Please any tips about how i could do this with Forge or Connect.