I am fully Jewish with me being unable to find 1 goy that I am related to. If I recently found that one of my paternal relatives (my great x3 grandfathers brother or paternal first cousin) is a kohen. My source is a quote i found about him, "Forabbink, Gyula Groszmann a kohanita." Or in English, "Our Chief Rabbi, Gyula Groszmann Hakohen." He was the chief rabbi of a small municipality in Hungary/ Slovakia. I would share a link to the pdf but it is kind of broken and the link no longer works. Would that make me a kohen? Also I carry the same surname.

My friend apparently, according to what you wrote, YES you are a Kohen which is a great honor (I would love to be a Kohen)- Congratulations on revealing your higher level of holiness! Just to be sure, you can check online to see old grave stones which should also say, by your male ancestors, that they were Kohanim, or alternatively they may have a picture of the Kohanic hand symbol (and usually also buried by the outskirts of the graveyard). That means that you (like other Kohanim) are worthy of many honors like receiving the first Aliya in the Torah reading and receiving many more Aliyot than anyone else; leading the Grace after meals ("Zimun" or "mezuman"); you give the Priestly blessing every holiday (and in Israel, every single day!); you can redeem first-born boys (receiving about 200$ each time) and more. This higher level of Kedushah (holiness) is connected with the fact that the Kohanim did not serve the Golden Calf, and are the chosen descendants of Aaron, the brother of Moses and chosen by God to be the first Kohen and be those who do the service in the Holy Temple in Jerusalem. Your holy family even merited to revealing the oldest known male-connected gene in mankind found in almost all male Kohanim in Israel, America and Europe (although I don't suggest doing that genetic test, for as soon as you are halachically a Kohen, the genetics are irrelevant). You should surely attend the synagogue more often as befitting your special status, and in order to reap the honors you deserve, and make sure to tell the rabbi there that you are a Kohen! As with most honors in life, it also brings more responsibilities, like observing a higher level of purity: not going into cemeteries- just staying outside of 2 meters of a grave or dead body (and not even standing under a tree which also shades over them), and not marrying a divorcee or convert. If even when your fore-fathers were religious Jews (probably at least your great-grandfather and his predecessors) the graves don't mention that they were Kohanim, that means that you may be a Safek-Kohen (="perhaps a Kohen") which is enough to obligate the aforementioned prohibitions but not enough to receive the aforementioned honors. In this case you should definitely consult with your local orthodox rabbi ASAP who may help you verify and clarify your status. Again, congratulation on your important revelation, and you should tell your brothers and sons as well!