Yes, it is.
Spanish flu is a subset of H1N1. In the graph you don’t understand, most of the points are for swine flu. Spanish flu is the baseline. The circled points are described as the variety of H1N1 called “swine flu,” which includes the biggie in 2009 (H1N1pdm09).
H1N1pdm09 is still with us today.
You have absolutely zero rational and evidentiary basis for your claim that H1N1 only applies to the Spanish flu of 1918.