Yes, they are. Solid in the sense that they're financially in a good place, which is the opposite of 2008. In fact, many of the companies that were buying up homes in my area were doing so in cash, no loan required.“Solid loans” that were primarily given to investment houses and transient / multiple residence owners in the upper 15% of workers aren’t solid.
The middle/lower middle classes and first time home buyers have been slaughtered in this market, but they didn't secure adjustable rate loans with little to no income/employment verification. The loans were well vetted and prospective homeowners were in a good enough place to secure their mortgage. Where these new homeowners are going to get bitten isn't with adjustable rates, but rather the surprises that will pop up because they waived their right to inspections.
What's missing in your premise is the fact that these corporations that bought up homes with the intent to rent them out don't have to sell if the market's not there to offset their costs. Yes, there's likely some companies that are looking to liquidate especially as the markets are rocky, but with rent costs at all-time highs, assuming that there's no bankruptcy then these companies are in no rush to move off their recently acquired properties.
There's also no evidence that I can find of these "upper 15% of workers" being forced to move back to the cities they moved out of originally. Sure, there's beginning to be a return to office, but that doesn't necessarily equate to selling your new home and moving back to the city. It means that they'll likely either find a new job closer to their home or commute.