Many things to unpack here...
Do female, private-practice, full-time orthopedic surgeons make less than their male counterparts? I'm wondering if the pay gap is still there for an apple-to-apples comparison or if its more broad, i.e. more females in peds (is there?) so "female" pay is skewed down.
Regarding your concern about universal healthcare... as someone who is a strong supporter of it, I can just tell you it is not going to happen anytime soon. The closest chance there was would have been Bernie Sanders winning the primary, and how did that work out? He got absolutely schooled, and his message of "let's have universal healthcare" was not enough even during a pandemic, which caused people to lose their jobs, which were tied to their healthcare, which Bernie's opponents constantly heralded as the correct way to deliver healthcare. If the message can't win then, when will it? Also, even if everyone agrees with medicare for all, people will still vote against it, as was seen in exit polling where medicare for all had a majority of support and Biden still crushed. Young people want medicare for all and vote for "radicals" like Bernie Sanders, yes, but older people already enjoy these scary "socialist" programs, and are not particularly concerned with changing the status quo too much. They wanted to beat Trump and the mainstream media told them Biden was the one to do it - so they voted for Biden. This will probably always continue to happen as the republican candidates become more and more extreme and democratic voters flock to the "safe" option.
Regarding salaries... european docs make less, but also on average these countries have a way less income inequality anyway. Nurses there make less, bankers, tech workers, literally everyone makes less there, that's what Europe is. Lower salaries are not mandated in a single payer system, you could cut US physician reimbursements in half and drop healthcare spending by a whopping 6%. If you look at the Lancet article on financing a single payer system its obvious that you can raise physician reimbursements, cover everyone, and pay less as a country on healthcare.
Also, the most "radical" politicians are the only ones who want to cancel every penny of student debt, even for physicians. The "moderate" democrats and republicans are the ones who are trying to "stick it" to "rich physicians" and want to cap any broad cancellation or even PSLF payment, which is interesting when all I hear is that it's the "radical" politicians who hate rich people like doctors...
The reality is that there is literally billions of dollars hinging on the maintenance of the status quo. To address your concern, that status quo means no medicare for all; however, it also means skyrocketing tuition, the corporatization of medicine, decreasing reimbursements, more paperwork, more authorizations, and less autonomy, which in my opinion is much worse than guaranteeing healthcare.