"If we were to stop all deaths — every single one around the globe — right now, we would add about 150,000 people to our planet each day. That would be 55 million people each year — "... This sounds linear, like a graph of it over time would be a straight line. I don't think that's how population growth proceeds.

A plot of Earth's human population from, say, 10,000 years BCE to the present is exponential, starting with barely a slope and then rapidly increasing and now heading straight up. Here's a good example: https://ourworldindata.org/grapher/population

Now on top of that you're going to, not only keep around those who would otherwise have died, but make their biological processes more youthful, including extending their childbearing years. And you think the additional births will be a linear increase? I call BS on that!