Had my frozen hot dogs gone rancid?

Where I live is currently in Covid lockdown, so when I was cooking dinner tonight, I decided to pull some old hot dogs out of my freezer and boil them. However, rather than sinking to the bottom of the pot, they floated, and during the boiling process, a sort of yellow foam could be seen coming off of them through holes in their skin. Finally, when I removed them from the pot after they’d been boiled, I noticed that they were unusually firm, and when I cut one open, the meat (or fat?) inside had gotten a bit of a yellowish hue.

When I checked the packaging, I saw that they’d had a best before date of 2019. While they had been in the freezer that entire time, and had never been defrosted, so I didn’t have to worry about them going bad from bacterial growth, but I remember hearing that frozen meat can go rancid from oxidation over time.

Is this what happened to my hot dogs? If so, would they have been safe to eat? Is there any way to tell if frozen meat is starting to go rancid, so that it can be eaten before it goes fully inedible? I figured "better safe than sorry" and threw them in the rubbish bin, and made myself something else to eat instead, but now I’m sort of wondering about what I should do in the future if this recurs.