Check out !worldnews@lemmit.online. The admin of lemmit.online has set up a bot that fetches reddit posts via RSS, making it much easier to make the switch and of course not getting any ads.
Also, these posts can then be cross-posted to help us create more content on lemmy native communities. Although I do recommend removing most of the post body when cross-posting. Alternatively you can turn the cross-post into a native post as if you simply were sharing content that you’ve seen on reddit, but with the perk of not having to load reddit.
You can make requests for subs to fetch at !requests@lemmit.online.
In the end we’re just using lemmy and lemmit’s bot as a simple RSS reader, so nothing illegal or even remotely unethical happening here.
Reddit, and that information, is still there. If you want to avoid giving them hits for advertisers, I recommend trying out teddit.net. It doesn’t use the API, so is unaffected by the new changes.
More generally, use https://libredirect.github.io/ to avoid tracking and advertizers on a whole host of extremely hostile services. Eg, it automatically sends you to a third party Reddit proxy like teddit any time you click on a Reddit link.