So I guess someone has to say it - do you bother to read the manuals that come with things or is that just for retards. The fence lock as a tension adjustment, yours is most likely out of adjustment per the description. The blade rise and lift does have a need to be greased but then it should have been from the factory. It also, get this has some adjustment and checks in the manual.
Did you square the blade to fence, blade to table and the like when you got it?
and did you get it new in box? Yes the mitre gage is chintzy so is every mitre gage packaged with every table saw that doesn’t say JET or POWERMATIC on the cabinet.
DId you test one in store before you bought it.
SOrry you have bad luck with Dewalt customer service but based on how you post I’m wondering it part of it might be your general attitude.