When using Primal, I can see that people have replied to posts but they don't always load, I guess because we aren't using any of the same relays. I haven't noticed this when using PosterChan, which I just found out about and don't know whether to fully trust yet.
The Amethyst Desktop app seems like the best way to use Nostr. It runs locally so there's no need to keep a browser tab open or use an extension to sign in, and it's compatible with the most amount of features such as groups.