There is no good answer here. In theory, you should be able to flash back to a previous version. But theory and real world do not always jive - especially if the flashing program reports you already have a newer version and will not let you roll back. The good news is Gigabyte lets you back up your BIOS so "in theory" (I know!) should your flashing fail, you should be able to recover. But of course, that requires you back it up BEFORE installing the new. Did you?
You might try Gigabyte tech support again and hope you get a different person. Complain that you would not have tried the F6e if they had not put it out there.
For the record, I never - as in NEVER EVER update my BIOS unless the new update specifically addresses a problem I am having. Most updates simply add support for new CPUs or RAM that came out after the board left the factory. In general, I go by the police of, "If it ain't broke, don't fix it!". Of course, hindsight is 20/20.
Last, check out the
DualBIOS feature in your motherboard manual. This is a Gigabyte feature where there is basically a factory reset backup copy of the BIOS installed when it came out of the factory. It may set you several versions behind, if it works, but that is likely better than where you stand now.
Otherwise, you may best be served going into "hurry up and wait" for Gigabyte to come out with a new (not beta) version.

Sorry I'm not of more help.