Since I’ve seen people asking, there is a native “Tootmarker” API (akin to Tweetmarker[0]; keeping your position within your timeline across devices/clients) already, but none of the clients are using it really.

Why? No idea.
Should they all support it? Hell yeah.

[0] https://www.tweetmarker.net

Tweet Marker

@moritz Not even the official app.
@lewin the “official” app was a one-off stint, bought for with Patreon money, from a contractor, to have something “official” in the relevant app stores, not because there was an intent to create a feature-full, native experience. Its lack of features and support for the most basic functionality is not surprising.
@moritz Well that‘s disappointing :(
@lewin Welcome to Mastodon’s development community.