On a personal level, get theft insurance on your bike. Costs me like 150 €/y for a 2000 € ebike, although some insurance companies do not cover street parking in some cities.

On a societal level, there are things law enforcement could do to make fencing less lucrative. Giving a shit about theft reports for one. For two, my city pays to get everyone's frame engraved with their national registration number, which will get my bike back to me if the cops find it and it makes the bike a bit less valuable because most people aren't looking to buy a clearly stolen bike.

The solution is bike lockers. It’s an important piece of public infrastructure that often gets overlooked.

I used to live in center city Philadelphia. One day I was walking down the street and I noticed a big guy on the other side with big loose shorts on walk up to a bicycle that was chained up to a signpost. In one smooth motion he whipped a big pair of bolt cutters out of his shorts, snipped through the chain, hopped on the bike and rode off down a side street. Like, I didn't even have time to think about doing anything or even yelling. Plus it's Philly - he might have ripped my fucking eyeballs out (Phillystines have a thing about the phrase "I'll rip yer fucken eyeballs out" although you see surprisingly few eyeball-less people walking around here).

There are angle grinder resistant u-locks which can last up to 5 min and waste several disks. They aren't cheap though and the thieves also could just cut through the rack.

https://thebestbikelock.com/security/angle-grinder-proof-bike-lock/

Bike thieves move fast, and a lot of time they are in cars, it's not always some random guy on the street. I saw a brand new Lexus pull up to a bike at a red light in a fancy neighborhood, guy was actively in the road and parked blocking the lane, and stole the bike in literally 40seconds and was gone. No license plates. I called it in but I doubt they did anything about it. And I'll never risk my life for a bike lol.