You could also use dedicated hardware to store your keys. Any FIDO USB key will do. I have a Yubikey that cost me less than 30 bucks.

It’s really handy, because I frequently use someone else’s device for work. All I have to do is plug it in, press the button on the key and enter the master password for the passkey storage. It’s like having a password manager on a USB stick.

And they can be hardware based as well. I have a cheap Yubikey USB dongle, which works as a passkey vault as well. Completely OS independent.