Dehumanizing is treating other humans as not, or not fully, human. For example, the term "human resources" is dehumanizing because it puts humans on the same level as other resources. If you're treating humans like you'd treat, I don't know, lithium or the ocean, you're dehumanizing them.
The more humans are treated as numbers on spreadsheets and other forms of computation, the more humans are dehumanized.
So both can be true: we're more dehumanized than in 1900, but while that does impact quality of life negatively, the overall quality of life may still be better than back then.
The question should be whether and how we can have both: overall quality of life without being dehumanized.
Social bonds and connections are integral to human flourishing yet are rapidly degrading and being replaced by digital pacifiers.
Worse, they won't even give you the dignity of a claim to contribution to society. Then the lack of contribution is weaponized against you.