My main complaint with Mastodon (the web version, at least) is that you can't easily browse different stances from within your native one, like you can with lemmy.
In Mastodon, I can't easily filter to see only toots from instance X or Y, my only options are either <all local toots> or <all connected federated instances' toots>
Various iOS and Android apps let you follow the ‘local’ timeline for other instances. I use Ice Cubes for iOS, but I believe a lot of other apps have this feature.