Let’s start with Atbash the get those letters in a better range
fdffdfedbfeecdbddedcdfdbbffdedbfeefceecdbecb
Convert letters to numbers using a=0
53553543154423133432353115534315445244231421
The numbers all range between 1 to 5. This is good for a Polybius square cipher
xzpsethcomplexsetwthdf
xzp73complex723df
Code #2
Observations
That \ is there as a hint and is not part of the passcode. It’s probably easier to find what keyword would fit before trying to rearrange things
Spoiler
The \ is really a hint on how to rearrange things. First let’s reverse the code without the \
ebd4rs9a4h6h2nf
\ means that you need to do a stepped transposition
e
b
d
4
r
s
9
a
4
h
6
h
2
n
f
Read going up from the bottom right F
fnh24shard694be
Code #3
Observations
24 numbers separated by dots.
Spoiler
Notice how most of the numbers following those “1” are in the 700 or 800 range. This can mean the start of decimal to Ascii range. Start be making pairs
1.857
127.7
4.209
5.194
1.738
5.76
449.2
373.1
1.707
2.185
2.398
1.787
For each pairs multiply the first number by the second
