I thought Twitter already had limits, tbh. It only ever has so many curated tweets for me, few of which are from accounts that I actually follow (even fewer from radical tweeters). After a few 'pages' it just says, 'no', and refuses to load any more. It's always done this. If I click on the profiles of people I do follow, many tweet daily and often. Twitter just refuses to include them in my timeline. It's one of the reasons I rarely use it. No idea what it would be like recently.
6000 tweets is only for people with Twitter Blue, and it counts scrolling past a series of tweets on your timeline as reading them, so it's really easy to hit that limit even as a paying bootlicker.
For those of us sane enough to not spend any money on that godforsaken platform, it's only 600 tweets, which is disgustingly easy to hit. Scroll a little through your timeline, open a few tweets to read replies, and you've hit your limit in less than 30 minutes.