assign free space Gparted - can not unmounted - /dev/nvme0n1p5

I think you can't allocate free space to your ext4 partition because there is your swap between free space and ext4.

Try:

• Right click on your swap partition and select Resize/Move
• Drag and move the partition to the left, Free space preceding must be zero and Free space following must be 45.19GB.
• Now, unallocated space and ext4 are next to each other.
• Right click the ext4 partition and try to resize it.

If you can't move the swap partition, maybe it is used by the OS. Check with swapon -s if /dev/nvme0n1p4 is listed. In this case, you can disable it with swapoff, then retry to move swap partition.

And if I'm not mistaken, /dev/nvme is used for nvme SSD on PCI-express slot, and /dev/sda is used of SATA drive.