Keep in mind that a gravel bike will get beaten and abused - lots of paint chips, rocks hitting the downtube, mud covering, etc. You certainly can spend $3500 on one, but realize that it will be difficult to keep it at all clean or new-looking for more than a few rides. There are many bikes in the $1500-$2k range that are nicely equipped, but not too nice - the kind of bikes you can beat the crap out of and not feel bad about.