I have cancer – what's the best EU country to get treatment?

I have come to the realization that I most likely have some form of cancer and would need to seek diagnosis & eventual treatment as soon as possible.

I am in the process of immigrating to the EU, but needing treatment on short notice throws a bit of a wrench in the works as my destination country has subpar public healthcare. My original plan was to arrange private healthcare once settled to work around that problem but it's a bit too late now. As a result I am effectively stuck with public healthcare only as I don't believe any insurer would cover what is now a preexisting condition. My origin country is also a lost cause in terms of public healthcare so there's no point even trying there.

I have a EU passport, work remotely and can effectively go anywhere. What's the least worst EU country to get state-funded treatment?