That isn't necessarily because people are working less hours per se, but easily because more people are under-employed now, working part-time jobs instead of full-time jobs. This brings your averages down.

Or job market regression. Combined with wage stagnation in the US over the past few decades, a decrease in working hours (depending on where the hours are dropping) would have to map to an increase in poverty and/or homelessness unless paired with a decrease in cost of living (which isn't happening here)

There has not been compensation stagnation in the US. When you include everything, total compensation has continued to climb.

Health benefits are expensive, have ballooned massively in cost, and are disregarded in the fake wage stagnation premise that gets thrown around.

The US has gone from 6% of GDP going to healthcare, to around 18-20%. That's where a lot of compensation growth has gone, paying that rising bill. It doesn't mean that compensation does not exist however, it's being spent on a service (that obviously should cost a lot less).

401k and similar compensation is disregarded by the wage stagnation premise.

The dramatic improvement in the US welfare state in the last 20 years is entirely disregarded. That costs a lot of money, heavily paid for by the top 1/3 who pay most of the taxes in the very progressive US taxation system. The share of US GDP going to the welfare state is now higher than other comparable countries like Canada and Australia, and it's climbing faster than both (ie accelerating away from them). That's an entirely disregarded factor in the quality of life for the bottom 1/3 who may find themselves needing to lean on the welfare state at some point, and or routinely draw benefits from it (that are not added into the income picture). When you look at the wage growth figures over the last 20 years, they do not show the large increase in welfare benefits being consumed. The point being, the picture is not nearly so dire as is often claimed.

Increased health care costs doesn't mean that compensation has gone up, many workers don't have health coverage provided by their employer. For people without employer-provided health care there are huge gaps in government-provided health care (often gaps created on purpose). Combine that with the minimum wage literally being unchanged in many states for decades... Not to mention employer plans' deductibles, coverage and copays can change as costs go up.