No. You can mine as many sentences as you want.
For instance, if you come across a lengthy anime series that is compelling to you, feel free to mine sentences from it until it ends. There are no limitations as long as you enjoy the process and continue discovering 1T sentences.
However, over time, there may come a point where you have mined most of the commonly used vocabulary from that particular source. At this stage, you might struggle to find enough new sentences to reach your daily goal. When this happens, it is recommended to limit the amount of time you spend immersing in that specific source. Instead, seek new materials to immerse in and start mining sentences from them.
Even if you immerse yourself in various sources within the same domain, it is inevitable that you will eventually exhaust the pool of new vocabulary within that domain. Therefore, switching from one domain to another is also important for making faster progress.