I'd recommend just using Atom. It is as widely supported as RSS but far better specified so your readers will have a consistent result.
JSON Feed is fine but provides very little benefit and isn't as widely supported. Having multiple feed links for the same content will give some users analysis paralysis. (What we really need is an update to the auto-discovery spec that says "these two feeds have the exact same content, if you support both formats only show your preferred format to the user")
I wrote up a guide for my recommended RSS Best Practices which while not aimed at how to create your own feed contains enough information to do that.
JSON Feed is in a catch-22. Not many websites use it (and none can use it exclusively) because not as many clients support it. Few clients support it because not many websites use it. While an auto-discovery spec would be great, having multiple feeds is currently the only way to add JSON Feed and break the cycle.
> What we really need is an update to the auto-discovery spec that says "these two feeds have the exact same content, if you support both formats only show your preferred format to the user"
You could do that right now by having 1 URL that changes what type it returns based on the request's "Accept" type. However, I don't know if any websites/clients actually do that, or if it would break older clients.
Yeah, it is a catch-22, but there is little reason to break it IMHO since it doesn't bring much extra to the table. My feed reader does support it but I would still recommend Atom. It is more mature, has more features and extensions and is supported everywhere.
The main thing JSON Feed seems to have going for it is that it isn't XML which honestly isn't a very compelling argument.
The accept type is a good idea. Unfortunately few static site hosts (which is common for RSS feeds) support this. And many CDNs don't either. It also doesn't play the best with HTTP caching.
JSON Feed is fine but provides very little benefit and isn't as widely supported. Having multiple feed links for the same content will give some users analysis paralysis. (What we really need is an update to the auto-discovery spec that says "these two feeds have the exact same content, if you support both formats only show your preferred format to the user")
I wrote up a guide for my recommended RSS Best Practices which while not aimed at how to create your own feed contains enough information to do that.
https://kevincox.ca/2022/05/06/rss-feed-best-practices/