Thank you for your help and response. Your response doesn't mention anything about Clockify however - if the client wants to keep using Clockify (due to being hesistant for change), is there any other way to go around this "integration problem"?

My other question is that to add contractors as "time tracking only" users, is it all free (included into the QBO Essentials subscription), or if we would have to pay any extra fees? - Thank you.