The default timeline you see on Twitter is curated and managed by Twitter's internal algorithm. Based on many factors, it attempts to show you tweets you will engage with, to keep you hooked in the app.
To help with this, Twitter will regularly show you tweets from people you don't follow based on interactions by people you do follow. The order of tweets is also altered, to try to show you more interesting content to make you stick around.
I signed up to Twitter in 2006. For many years the timeline was an ordered list of the latest tweets, with no interference from these recommended tweets that you might like, but didn't ask for.
Luckily, it is very easy to view your timeline in its original, stripped down form, if that's how you want to browse Twitter. And it's also easy to switch between both versions of your timeline.
Activate the chronological timeline
At the top of the Twitter web app and iOS app, there is a star icon.
Clicking or tapping on that will bring up a menu with the option to change from “Home” (the default) to “Latest Tweets”.
It's that simple.
Now your timeline will show the latest tweets in the order they are posted, and should no longer see recommended tweets that have been liked by others.
Annoyingly this setting does not sync between the web and iOS apps, so you have to change the setting in both apps independently.