Every test to do to exclude oral bacteria?

[Braccobaldo]

Hi, i'm a 18 years old male that suffer from almsot a decade of fecal bb, mainly from mouth but sometimes nasal. When it become nasal i start to fill rooms in minutes but also when it is only or mainly from the mouth it is pretty bad.

I've tried oralbiotics, Chlorhexidine, tongue scraping and ultradex mouthwash without success so i need to exlude at a 100% rate the oral bacteria problems in order to move on on the next possible causes.

I have post nasal drip due to plant based allergies but i've read that without bacteria it don't smell THAT bad, by the way i'm working on it.
Also even when I scrape my tongue i still have a white/yelllw patine that remain so I need test also for this.

I want to do all the test for excluding a bacteria problem in the mouth, throat and tongue.
Someone more informed than me can point me in the right direction with a list of test to do?

Im from South europe. I know some clinics that do this like the one from doctor nunes in spain and italy but it cost like 1100 euro and if possible i would like to do the same test without spending that much considering my bb could originate from somewhere else

That problem are mentally killing me from the inside, i know all of you can relate so please if you have some info help me i will be extremely grateful