The work is not equally easy splitted between the languages that you need to support, so if you are supporting a language that is spoken by limited amount of people then you have to face more phone time, than e-mail or chat support, which for a longer run can be very exhausting. Some of the quality checks on my specific language was unfair as on many occasions the person who did our evaluations could not even speak our language and deducted points for certain grammar specifications that would not make sense in english or via Google translator, which then obviously affected our perfomance and neither our team leads could do anything against this nonsense. Of course most of the time the best performing folks were on the FR, EN, ES, IT line as you had more time on e-mails where you could close a case in seconds not like on the phone where on multiple occasions a day you received an extremely confusing case that required more time, focus and support than just a few minute call but then on the other hand it was not viewed as a great work opposed to the colleagues who kept closing items by sending a very generic e-mail template and then close the case again which obviously not solve the issue just move it further to another unfortunate colleagues in the future.
When help needed from the Seniors it was many times that the knowledge of the senior colleague was questionable and it was just better to hang up the phone and get randomly assigned to someone else.
On the other hand progressing further was easy within the company if you knew the right people, or worked hard.