Had a adjudicated guilty withheld. Is that a guilty plea with a disposition withheld adjudication?/

If that is the only case you have on your record, you should still be able to pass a background check. However, if you have any misdemeanor crimes of violence, that may present a problem.
If you are denied, it simply means that a reputable dealer will not sell to you. No further legal action should be taken against you, unless you have seriously misrepresented some information.

I don't quite understand if you have a prior record or not and what the burglary to a dwelling has to do with your eligibility. If this was a juvenile charge or a charge as an adult, etc. If you do not have a felony conviction or a conviction or a withhold to a domestic battery, you should be eligible to purchase a firearm. If other attorneys have reviewed your record, know the specifics of your situation, I would not quarrel with their conclusion that your are eligible in Florida to purchase a firearm. There is no harm in applying and trying to make the purchase.