Race being a social construct doesn't mean it doesn't have social implications. The fact that race is a social construct doesn't change anything about the negative impact of racism or the need to address racism in America, it just further proves how idiotic the arguments of the racists are. A social construct that has existed for 500+ years is still a real thing socially and can still be the basis of affirmative action, reparations, etc., it's just not a real thing biologically.
Subspecies are real and based on measurable genetic and phenotypic differences between populations.
Race is not real because there's no actual genetic differences that align best with race. If you want a scientific article on the subject, this is the best one I've seen. Genetically if we were to divide humans into genetic ancestry, then the most mathematically supported model would be 21 separate groups (though the differences are so vague there isn't that much difference in the modeling if you use as few as 12 groups or as many as 40) and over 97% of humans are mixed between two or more of those 21 groups. Plus none of the 21 groups would be different enough from each other to rise to the level of subspecies.
Human ancestry correlates with language and reveals that race is not an objective genomic classifier | Scientific Reports
Each of the colors represents a different genetic lineage. Notice how each of the different geographic areas are made up of people of completely different genetic backgrounds, and even individual groups are made up of different colors themselves meaning they have mixed genetic background, plus some of the genetic backgrounds are shared across different continents. There's no way to look at that chart and decide that 4-5 races is the most sensible way to divide people.
That's another way of showing the data. Notice that there is less genetic difference between the east african and west asian lineages than there is between east african and south african. Notice that native americans are closer genetically to many asian groups than some of those asian groups are to each other. Notice that southern european and northern african lineages are closer to each other than southern europeans are to northern europeans. Notice that the south indian and south asian (north indian) lineages are so different from each other that they're in two entire different sections.
Don't forget that those genetic groupings don't even represent actual human populations today either. For example, the average person in Iran today is some mix of the south asian, west asian, north asian, and arabian ancestries, with every person in Iran being a different mix. Whereas someone from Libya is a different mix of arabian, west asian, north african, southern european, east african, and other ancestries.
There's no way to look at that data and decide that our modern racial categories make biological/genetic sense.