However, since you already have SportsNetNow, you can either watch it through their app https://www.snnow.ca/ and cast it to your Roku device or load it on a laptop through a web browser and then connect it directly to your TV via HDMI cable. https://watch.sportsnet.ca/tv
Not sure about the Stanley Cup playoffs though, as the 2023 coverage is through ABC, ESPN, TNT, TBS and Hulu. TNT has the Stanley Cup Finals so not too sure how that works with SportsNet and other carriers showing the games.
Seems like you should use the Sportnet subscription and cast it to your Roku device for the regular season and then plan on subscribing to a service available in Canada that carries the above networks just for the playoffs. (most/almost all of the channels/apps are month to month subscriptions).
Roku Community Streaming Expert Just another Roku user... I am not a Roku employee. Insignia RokuTV, Ultra 4660, Premiere+ 3921, Express 4k+ 3941, Streambar 9102