I like the functionality with the home= cheat code, thanks to UnionFS. However, I would like this functionality to mount the image at the / level, not /home, or /home/knoppix, or whatever. I would like to create the illusion of a full writable filesystem, with the changes written to an image on my USB stick. Is this possible, and if so, how?

Crucial MX500 500GB 2.5" SATA III Internal SSD CT500MX500SSD1
$52.99
SSD 880EVO SATA III 2.5 4TB INTERNAL STATE DRIVE
$214.99
Samsung 860 EVO 250GB, SATA III, 2.5" Internal Solid State Drive - Black...
$30.00
Western Digital Blue 3D NAND 500GB Internal 2.5" (WDS500G2B0A) SSD
$47.99
Western Digital WD Blue 3D NAND 500GB 2.5in SATA III Internal SSD WDS500G2B0A
$41.99
M.2 SATA SSD 2280 128GB 256GB 512GB major brands | Very Good health
$35.99
2 PACK 128 GB SSD M.2 2280 SATA Solid State Drive Major Brands, Samsung, LiteON
$28.80
M.2 NVMe SSD 2280 Single Notch 128GB 256GB 512GB | Very Good health
$38.99
Samsung 860 EVO 250GB SSD MZ-76E250 2.5" SATA III Solid State Drive
$39.99
128TB External SSD Solid State Drive Hard Drive Disk PC Phones Mac Games Videos
$97.60