All three VPN players support the big four: iOS, Android, Mac, and Windows.
ExpressVPN also supports Linux, routers, and Kindle Fire. It supports Xbox, Playstation, and the Nintendo Switch as well as browsers Chrome, Edge, and Firefox. When it comes to TV support, ExpressVPN lists Apple TV, Amazon FireTV, Samsung, Roku, Nvidia Shield, Chromecast, LG Smart TVs, Android TV, and others that require more of a manual setup process. Additionally, it offers setup instructions for Synology and QNAP NAS appliances.
In addition to its big four clients, NordVPN lists Android TV, Linux, and Chrome and Firefox extensions on its download page, but has a support page for installing NordVPN on other platforms, including routers, Raspberry Pi, and NAS boxes including Synology, Western Digital My Cloud, and QNAP.
Besides iOS, Android, Mac, and Windows, Surfshark also supports Linux, FireTV, Apple TV/iPhone, and what it calls “other TVs.” It supports Xbox and Playstation as well as browsers Chrome and Firefox.
The fact is, all three products support a reasonably wide range of devices, but we have to give the win to ExpressVPN. You can keep digging down in the support pages and there are more and more devices with install tutorials, the deeper you dig.