There's still an option for a chronological timeline. https://twitter.com/settings/account#personalize_timeline and uncheck "Show best tweets first". It will still inject a block called "In case you missed it" from time to time but you can dismiss it.
Mastodon... it's a platform, not a single entity that I can use.
That might be the tradeoff that has to be made. Pick a Mastodon instance whose administration you trust not to screw you over. If they do you can move to another. If you go with a single entity, you're going to be stuck when they mess with you. Like with Twitter.
Well, it goes you a chronological ish timeline. It still insists on trying to insert blocks of "content you might have missed", and it still has crappy conversation views that can't be turned off.
A strictly chronological timeline is only available via third party apps.
Twitter had that chicken-and-egg problem too, but do you know how we solved it? We all joined Twitter and then told people we wanted to follow that we were there.
With the difference, that back then Twitter didn't exist. Only in form of IRC or such and Twitter could distinguish from that. A new service has to be unique in a new way.
Mastodon... it's a platform, not a single entity that I can use.
That might be the tradeoff that has to be made. Pick a Mastodon instance whose administration you trust not to screw you over. If they do you can move to another. If you go with a single entity, you're going to be stuck when they mess with you. Like with Twitter.