I have Google Chromecast on my LG 32LJ500B television set. It freezes on practically everything but YouTube. I don't have a cable account, I just watch TV shows from Canadian networks. I also have a smart Tv and no freezing ever.
After a year, Google replaced the first dongle I bought, but the problem is back, worse than ever.
I would like to try Roku before getting a new smart TV. Roku was recommended to me but there are so many models I don't which one to choose.
The link is for the US, but I think if you are in Canada it will automatically direct you. (If not, there's a region choice way down at the bottom of most roku pages.) There's nothing specific in your post that tells me that you want any specific model so you'll need to determine what features you want. The lower-end models that say "single-band wireless" are 2.4GHz Wi-Fi only. The ones that say dual-band do both 2.4 and 5GHz. (Some people care about that – some don't – same as many of the other features you get on higher end models.)