Surfshark users are not exerted by any speed, bandwidth or data limits.
Nevertheless, please note that a little bit slower speeds and response time (ping) with VPN compared to the ones without VPN may be experienced. The speed may decrease by 20-30%.
However, there might be cases when connecting to a VPN will even increase the speed of your connection. That might happen if your internet provider is throttling the speed in general or for some specific websites only.
If the connection speeds slow down considerably or the slower performance than usual when connected to the VPN can be observed, please check this article of ours.