I have never even heard of Caesar Geurini’s before. Just did a quick search and they look like fancy guns! Just seen a few prices in the 6-9k range so I'm guessing you were just looking.
I didn't even know Benelli made O/U either but they are well known for making great semi's that hold up real well. I know several people that hunt with them and will never switch back to another. Did a quick search and seen two models one of which is at the top of your budget.
Krieghoff is another i see a lot of people use but they are pricey as well. Don't know if they make anything under 5k or not
SKB is one i forgot about and have a little insight on. My uncle who just went out of business last year was a SKB dealer. His daughter, her husband and their daughter along with some others at the club all shoot with them. Nice guns BUT they are finicky and prone to certain parts breaking. My cousins husband started his own shop and bought my uncles stock so he's selling them now and is getting into gunsmithing so fixing them as well. Even before that he learned how to tear down, fix and even make parts for the SKB and keeps a kit in his vehicle with common parts and tools when they go shooting so he can fix on the go. When i was getting back into it he wouldn't sell me one because he didn't want me to get discouraged and get back out of it if i had a problem gun. They've had to send a few back too. Last year their daughters gun had the rib coming lose so that went back. I'm not sure if it's just certain models or not but when they are working right they are nice guns. They also shoot a lot, maybe 2-3 times a week and around 400 rounds each a week for maybe 45 weeks of the year. Only time they don't is when the weather is real bad.
If you're not dead set on a O/U and will only be shooting trap with no doubles there is the Browning BT-99 too.
Miroku makes nice stuff from what i hear but lots of people like the older stuff not made in Japan or Turkey. I guess you might call them Belgium or Italian snobs?
Another thing to think about. Like someone else said get one that fits good but even when you do that you may think about adding an adjustable comb and butt pad to the stock so you can fine tune. I have the comb on mine, you can move it up and down plus left and right. The pads you can move in and out plus up and down and i want to add one to mine at some point. It's not a cheap add on but it's not break the bank pricing either.
Oh and i get that not buying used guns. I know lots of people like that too.