Comment by Tepix

Which instance are you on? Mastodon is decentralized, there may be servers that are overloaded whereas other are fast. Like email.

I haven't noticed any big differences in speed, i use both Mastodon for iOS and Pinafore (https://pinafore.social/ ), a PWA. Just add it to your homescreen and it will behave like a native app (and sometime in 2023 Apple has said they will add push notifications to PWAs).