Amazon Firestick and Roku give you access to many of the streaming sites listed along with a number of others. You only pay for the devices to get them set up and they're fairly inexpensive - there's no continuing charges after that. An added benefit of the Firestick, if one has DishTV at home, is the Dish Anywhere APP which allows you to watch all your Dish channels and local stations over the Internet. (I believe you can install a Roku APP on the Firestick and run it from there as well once you have an account set up, but as I recall you need to set up the account thru an actual Roku first.)
The other thing I've done in my RV for when I'm camping with limited or no Internet is to download a lot of old favorite movies and TV series onto a Neumi Atom 4K device (www.Neumitech.com) that, like the Firestick and Roku, interfaces to the TV (or HDMI switch) via HDMI connection. To download the movies and TV shows I use the StreamFAB application on my home Desktop. It has access to a number of the streaming sites listed and has the ability to remove the ads from anything downloaded as well. I do post-process what I download to get SD, HD and FHD formats that are compressed for the Neumi to save space and get more loaded on the MicroSD card I use, but that's not an absolute requirement for the Neumi.