Shrink Boot Volume size (in always free tier)

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Currently, I have one Always Free VM, the boot volume of which is currently 200GB (the max amount allowed on a free account).

Now, I have to deploy a second instance, which is why I have to shrink this boot volume (i.e to 100GB), however there seems to be no easy way to do this.

I cannot create a second smaller volume and move everything over, since the free account does not allow for more than 200GB of block volumes.

The only option I see is creating a backup of the volume and then restoring to a smaller volume, but I am unsure if this is possible because of the partition size.