@Nestacdo Well, "=" in the end makes me think that top layer is base64 code.
Decoder gives me this

It's not base64, there's 3 equal signs being used as padding. you can only have 0, 1 or 2 on the end.
also, the length of an encoded base64 string must be a multiple of 4, since it converts 4 base64 digits into 3 bytes. the string given has a length of 1741 which isn't a multiple of 4

that could possibly be because Operator accidentally put some extra padding characters but 0, 1, or 2 is standard and a direct consequence of how the encoding scheme works

what i noticed immediately is that there is a 8 character "phrase" repeated throughout the string but some letters are changed between each

to break it apart and demonstrate:
QDAM BRGE
YDAM BQEA
YDAM JRGA
YDCM JAGA and so forth. i split it into groups of 4 digits since four base64 digits = 3 bytes
the left column definitely show some kind of similarity, the right column seems to be random but there may be something there since, to be perfectly honest, i kept seeing the phrase "GAY" and "GEY" repeating over and over and over (GA and GE come from the right column pretty much always)

my first guess is that there's probably some preprocessing we have to do to this string