Hi and Welcome!
So you want a clean install again. Formatting the drive is not avoidable (but you can do a "quick format") then.
I fear doing that as the cells or blocks of an SSD drive get used and cannot be moved with defag as XP does not have a "trim" function.
I guess, this small SSD doesn't have that either.
On flash based storage, you don't want defragment for two reasons:
a) it is useless
b) it adds additional wear to the drive
So the question is "If I do a complete format the SSD will all the blocks or cells be wiped clean and so the drive runs faster and cleaner?"
No. This is low-perfomance stuff, and the only improvement you get is from the removal of all the crap and bloat you (and Dell) installed previously.