I have taken a job at a company that I deeply respect, being promised the opportunity to see the inner workings, the problem solving aspects and get to work in a competent team, in a field that is highly interesting to me.
The offer almost struck me as too good to be true, which it turned out to be - I am now working alone on a different floor than "my" team, doing literature research on a topic which has nothing to do with my education or interests, getting almost no input and on top of that, I am being treated with very little respect by my boss. I am doing nothing remotely related to what I was told.
Currently I am still in my old job as well, which pays a LOT better - I still have the opportunity to go back to it if I wanted to.
But I am afraid that by quitting after only a few weeks, I will lose my chance to work anywhere at all at said company, or worse, not get a job in any field, since I might take a hit to my professional reputation if I quit.
How can I quit or address my wish to quit without taking damage to my reputation, making enemies, etc.?