Hi Damon

Did you find a solution?

For Umbraco 13, if anyone needs to uninstall Umbraco Forms, the following achieved that for me:

-- Delete the Umbraco key if it exists
IF EXISTS (SELECT 1 FROM umbracoKeyValue WHERE [key] = 'Umbraco.Core.Upgrader.State+UmbracoForms')
BEGIN
    DELETE FROM umbracoKeyValue WHERE [key] = 'Umbraco.Core.Upgrader.State+UmbracoForms';
    PRINT 'Deleted UmbracoKeyValue entry.';
END
ELSE
    PRINT 'UmbracoKeyValue entry not found.';

-- Drop Foreign Key Constraints only if they exist
DECLARE @constraint NVARCHAR(255);
DECLARE @table NVARCHAR(255);
DECLARE @sql NVARCHAR(MAX);

DECLARE constraint_cursor CURSOR FOR
SELECT fk.name, t.name 
FROM sys.foreign_keys fk
JOIN sys.tables t ON fk.parent_object_id = t.object_id
WHERE fk.name IN (
    'FK_UFFolders_UFFolders_Key',
    'FK_UFFolders_UFFolders_ParentKey',
    'FK_UFForms_UFFolders_FolderKey',
    'FK_UFForms_UFFolders_Key',
    'FK_UFForms_umbracoNode_id',
    'FK_UFRecordAudit_UFRecords_Id',
    'FK_UFRecordDataBit_UFRecordFields_Key',
    'FK_UFRecordDataDateTime_UFRecordFields_Key',
    'FK_UFRecordDataInteger_UFRecordFields_Key',
    'FK_UFRecordDataLongString_UFRecordFields_Key',
    'FK_UFRecordDataString_UFRecordFields_Key',
    'FK_UFRecordFields_UFRecords_Record',
    'FK_UFRecordFields_UFRecords_Id',
    'FK_UFUserFormSecurity_UFForms_Key',
    'FK_UFUserGroupFormSecurity_UFForms_Key',
    'FK_UFUserGroupStartFolders_UFFolders_Key',
    'FK_UFUserGroupStartFolders_UFFolders_FolderKey',
    'FK_UFUserStartFolders_UFFolders_FolderKey',
    'FK_UFUserStartFolders_UFFolders_Key'
);

OPEN constraint_cursor;
FETCH NEXT FROM constraint_cursor INTO @constraint, @table;

WHILE @@FETCH_STATUS = 0
BEGIN
    SET @sql = 'ALTER TABLE ' + QUOTENAME(@table) + ' DROP CONSTRAINT ' + QUOTENAME(@constraint);
    EXEC sp_executesql @sql;
    PRINT 'Dropped constraint: ' + @constraint + ' from table: ' + @table;

    FETCH NEXT FROM constraint_cursor INTO @constraint, @table;
END

CLOSE constraint_cursor;
DEALLOCATE constraint_cursor;

-- Drop Tables only if they exist
DECLARE @tablename NVARCHAR(255);
DECLARE table_cursor CURSOR FOR
SELECT name FROM sys.tables
WHERE name IN (
    'UFDataSource',
    'UFFolders',
    'UFForms',
    'UFPrevalueSource',
    'UFRecordAudit',
    'UFRecordDataBit',
    'UFRecordDataDateTime',
    'UFRecordDataInteger',
    'UFRecordDataLongString',
    'UFRecordDataString',
    'UFRecordFields',
    'UFRecords',
    'UFRecordWorkflowAudit',
    'UFUserFormSecurity',
    'UFUserGroupFormSecurity',
    'UFUserGroupSecurity',
    'UFUserGroupStartFolders',
    'UFUserSecurity',
    'UFUserStartFolders',
    'UFWorkflows'
);

OPEN table_cursor;
FETCH NEXT FROM table_cursor INTO @tablename;

WHILE @@FETCH_STATUS = 0
BEGIN
    SET @sql = 'DROP TABLE ' + QUOTENAME(@tablename);
    EXEC sp_executesql @sql;
    PRINT 'Dropped table: ' + @tablename;

    FETCH NEXT FROM table_cursor INTO @tablename;
END

CLOSE table_cursor;
DEALLOCATE table_cursor;

PRINT 'Umbraco Forms key value, tables and constraints removed successfully.';

is working on a reply...