Spongy roots= root rot?

I know slimy soft roots that fall apart indicate rot, but what is this? Is this rot?
They are a little spongy but still solid where it is thicker

This is a pothos

Getting 8hours of artificial light rn cuz winter

I left it in a plastic bag for a day and a half and it stayed too moist so I know a little bit of rot occurred at the tips of the roots,

when I took it out of the plastic bag the soil smelled musty. I almost returned them but the plant store reassured me.

I just took it out of the bag and trimmed root tips but if this is rot then it’s way worse than I thought

3 leaves had minor browning at tips everything else seemed okay

I bought last week and sprayed with safers soap after taking out of the bag, the soil was still moist so I know I was risking it

If it’s not rot why do they expand and get spongy. And fuzzy like this

Only watered today after rinsing, trimming and repotting