All that 5g speed will be shared between all the users on that cell.
Even if the base station was infinitely fast, it would be limited by the speed of its backbone connection (fibre connection to it) divided by number of active users.
Looks like its not all that fast for some -
5G Technically
So, why are some 5G connections so slow? The first, and most impactful, reason is that the far-reaching 5G signals that have powered the vast majority of carrier rollouts in the US – especially from AT&T and, to a lesser extent, T-Mobile – have used low-band carrier frequencies. These frequencies (850MHz for AT&T and
600MHz for T-Mobile's early efforts) can reach
miles from their towers. The downside is that their speed capacities are generally below 100Mbps in real-world conditions, right in line with what could already be accomplished with a solid 4G LTE connection.
Another important factor is widespread use of a technology called
Dynamic Signal Sharing (DSS). This protocol allows carriers, including AT&T and Verizon, to use the same spectrum bands for both 4G LTE coverage and 5G coverage. The benefit is that some existing equipment and spectrum bands can expedite 5G rollouts by eliminating the need for new construction and spectrum license acquisitions.
Unfortunately, while the 5G side of DSS is legitimate 5G, of a sort, its actual performance is, in
Verizon's own words, "comparable to [its] award-winning 4G LTE." This is due to a combination of factors, including congestion, the limitations of older hardware, and the same reliance on low-band frequencies.
Simply put, the most widespread types of 5G currently available in the US all fall under the category of 5G services that are no faster than 4G, and offer relatively little in the way of comparative benefits aside from being widely available.
https://www.zdnet.com/article/why-is-my-5g-so-slow-comparing-the-hype-to-the-reality/