I think it's really complex because a particular condition might contribute directly to one person's severe illness or death with covid, but in another person it might not.
Broken bones is another one. My gut says the reason this one is included on some lists of underlying conditions isn't so much because there's anything directly pathological that causes a former bone break or fracture to worsen covid.
I wonder if it's more because large numbers a majority, I think, certainly of adults of the people who break or fracture bones are older, many elderly, and have a string of other conditions already -- osteoporosis, arthritis, dementia, etc etc.
It's not the fracture itself that causes the increased risk, it's the intersection of the likelihood of a recent break x age x other potential conditions? Certain conditions predict other conditions, statistically if not in every case.
I could be wrong but I don't think it's true that you're at increased risk of a severe outcome from covid because you broke your arm when you were 8.