I’ve been happily using a 9” Kryptonite Evolution since 2016. Even has marks on it from failed attempts to steal my bike once or twice. And by marks I mean just marks to the surface not gouges. Obviously if someone’s serious about stealing your bike they’re pretty much going too, but this little beauty has certainly seen off the opportunists. I lost the spare keys one time while moving too and Kryptonite replaced them free of charge. Serial numbers are on the keys. Amazon has one at £43.89 which is less than I paid 5 years ago. Kryptonite Evolution Lock U- Bicycle https://www.amazon.co.uk/dp/B06XCDZND2/ref=cm_sw_r_cp_api_fabc_70KD45EN6QYAVEA4W33J
Home Depot and probably every local bike shop (a bunch around Davis like Ace Wheelworks and I've used JRA in Medford before) sell some really long cables that you can secure to a good ulock like one of these bad boys.
If the OP is storing their bike outside too and in one spot, say outside their apt, go ham. Ulock the frame + front wheel (it's the easiest to steal) to a solid surface that can't easily be cut or broken. Cable lock the seat post, rear wheel and front wheel to the ulock. Then chain lock the bike too for good measure since those are apparently a bitch to cut.
Even better - try and store the bike inside if possible. At Davis you can lock your bike inside that secure bike area next to the T stop. Find places like that if possible, it makes it slightly harder to steal a bike. Inside your apartment or friends place is probably the best though.