First of all: please try to write your posts a bit more with "structure" - it's really hard to read your endless never-ending writing...
How did you put rockbox on it? With the rockbox utility?
What iPod classic / video is it, which generation?
With your formatting you did two things absolutely wrong:
1.) exFAT is not good, you need FAT32
2.) you removed your rockbox installation with that
Here are my suggestions:
disconnect the iPod from the PC and
1.) Boot into Apple's diskmode (completely switch off iPod and then hold down SELECT+Play together until the disk mode is shown)
2.) Switch to Apple's firmware by turning off the iPod, then turn it on and immediately lock the HOLD switch.
With 1.) you should be able to reformat it with FAT32 when connecting it to your PC;
after that you can put the ".rockbox" directory on it again and it'll boot again in rockbox
With 2.) you should be able to restore it with iTunes after connecting it to your PC;
after that you can repeat the installation procedure for rockbox
Rockbox bootloader USB is (in my oppinon) not very stable and you should not change the format in this mode.
Look at the instructions here (including instructions for switching between Apple and Rockbox modes):https://files.freemyipod.org/~user890104/bootloader-ipodclassic.html
(assuming you have a 6th or 7th generation device, the older ones are officially called "iPod Video" - but some call them also "iPod Classic", 5th Gen or 5.5th Gen)