No more space in root filesystem, how could I increase the size?

Good news! pvscan shows PV /dev/sda10 VG fedora lvm2 [141.56 GiB / 77.56 GiB free] — so you should be able to add up to 77.56GiB to any of your filesystems. I'd suggest adding it in smaller blocks (like 10GiB), so you have a reserve to put into /home if you decide you need growth there later.

This is a relatively well-tested and generally safe operation, but all root-level volume and filesystem operations have some risk — make sure you have a functioning backup first. Then....

You can extend your root logical volume to use the free space with lvextend, like this:

sudo lvextend --size +10G --resizefs /dev/fedora/root

(Or -L and -r instead of --size and --resizefs, if you prefer short options.)

More general answer for LVM:

Firstly - make sure you have additional unpartitioned storage. Then:

1. Use fdisk to create new partition (safer than expanding existing one)

2. Use pvcreate to create physical LVM volume:

   pvcreate /dev/sdxx
   

3. Use vgextend to extend existing LVM group using new physical volume:

   vgextend groupname /dev/sdxx
   

   You can get group names with vgdisplay

4. Use lvextend on lvm mapper to expand lvm volume:

   lvextend -l +100%FREE /dev/mapper/xxx
   

5. Grow the filesystem:

   xfs_growfs /dev/mapper/xxx
   

   Or

   resize2fs /dev/mapper/xxx
   

The / filesystem may be a particular challenge, as that needs to be supported by the boot loader.

This answer doesn't specify how to accomplish the requested task, but does provide a workaround.

Another option: find a sub-directory (e.g., /big/) which has lots of data. Then copy that data onto your 60GB of space, mv the directory with lots of space (e.g., mv /big /bigback), and mount your 60GB (or a portion of it) onto /big. After confirming everything works as expected, rm /bigback to re-gain space on /