This is the 204th most frequent Slovak word.
zároveň
At the same time.
Here, 'zároveň' is used to describe two actions happening at the same time.
Umývala riad a zároveň telefonovala.
She was washing the dishes while on the phone.
In this usage, 'zároveň' is emphasizing a simultaneous perception of the job's demand and its rewarding nature.
Táto práca je náročná, ale zároveň veľmi odmeňujúca.
This job is challenging but also very rewarding.
In this sentence, 'zároveň' connects two roles ('friend' and 'mentor') that are simultaneously attributed to the subject.