Are Windows 10 and 11 considerably more secure than the old versions?

They (especially Windows 11 on supported hardware) are far more secure than older versions of Windows.

That said, I don't really consider Windows "secure", when it's still filled with legacy cruft that was written before Microsoft's focus on secure coding. We are still seeing font exploits in 2022, FFS.

The track Windows 11 is headed seems like a decent approach given realities. For whatever reasons, Microsoft's efforts to eliminate legacy cruft has proved unsuccessful/untenable, so the next best compromise is to harden the OS against itself and everything else.

Most of the time, the problem lays with the users. Once (a long time ago) I RDP'ed into a Windows Server 2003 (or so) for some checking and saw it running a eDonkey or some other P2P download utility, as Administrator.

They’re fine, but with any desktop operating system (including macOS and Linux) there’s always some risks involved, depending mostly on user behaviour.

For something more foolproof and secure, consider iPadOS or a Chromebook.

Here’s a useful resource: https://techsolidarity.org/resources/basic_security.htm

It isn't secure from MS pushing updates that will revert some settings to default. I don't remember older versions doing that.

Looking at the number of processes run with administrative priviledges, i would say, no.

If you are behind a NAT then you may consider your any OS safe. But I have no idea about state-of-the-art of NAT hacking, maybe some of them are flawed.

Windows is not secure, it doesn't have any proper permission system, any process can read/write files, send network requests to anyone without the user noticing anything

It can even change system settings without you noticing

You should feel naked when you manipulate sensitive data with Windows, because you are indeed naked

Hence why most companies forbid their employees to use windows with public internet access for work