⋅ swap partition vs. swap file https://askubuntu.com/questions/904372/swap-partition-vs-swap-file so such a file may sound normal. Unless you also have a swap partition. Then check which one is active on your system, you may remove the unused one.
⋅ is this the same machine and installation as in Change Home Folder Location ? Remember here you have something weird : « sdb is your SSD. I’m a bit bugged that sdb shows no partition (…) might suggest later issues - be aware your current setup may not be perfect as is. »
⋅ when someone suggests some commands, please post their outputs here.
cat /etc/fstab
lsblk -f | grep -v loop
df -Th | grep -v loop
were precisely meant to « visualize » your discs and partitions, how they are organized and if/which ones are automatically mounted at start, or not.
⋅ sdc1 is a strange case. Might have been an iso image of an older partition ? Did you ever try to clone a system or a partition ? I just hope here it was not an actual partition, not yet mounted…