No, I’m not calling any of them rip offs. Artists inspire one another all the time, and their works can be similar and line up thematically. That doesn’t mean they are “rip offs.” Dune, SW, and Barsoom are all in the same vain, sci-fi/fantasy, with Barsoom predating both Dune and SW. Therefore in the timeline Barsoom comes first and spawned a ton of sci-fi works and ideas.

I know very little about the Barsoom series from a story standpoint, other than the influence it had on the sci-if/fantasy works generally. But Lucas even said the Barsoom series was a huge influence to him when he penned the original SW, just as he said of Dune.

Here is a great article on the subject of Barsoom and SW:

https://wealthofgeeks.com/why-john-carter-of-mars-is-the-original-star-wars-film/