On paper you don't have to do passport or security as you are not entering Schengen and Serbia's security is deemed equivalent to EU standards. However, Wizz arrivals and Ryanair are P2P operators who are not set up to look out for connecting passengers. Both use the same area at BER (the lowcost airline section aka T2) so you could theorectically deplane, walk into the building and over to the Ryanair gate. W2 from BEG seems to arrive in Z42/ Z44 and FR to DUB leaves from B42 / B44, so its literally the same gate area.

https://ber.berlin-airport.de/de/ori...ive-karte.html