Get two locks to use at the same time, best are locks that are approved for insurance reasons in the country they are common but which are not common where you park your bike.
In my country, the Netherlands, we usually have a ring that connects the rear wheel to the frame of the bike, and does not allow much movement to the wheel when engaged. This kind of lock can be broken, as can any kind of lock, but for a thief unfamiliar with it, it is likely the reason to steal the next bike which has a more familiar lock.
You will need to lock your bike to a solid object, of course, and for that you might use a strong chain with a top quality padlock, of the newest design that is not common yet where you park your bike.
I have always uses a cable as second lock, as I found the chain damage the paint on the one bike where I had to use it, but I do not park very expensive bikes.
My second line of defence is that my bike is less valuable than the one next to it while being at least as well locked. This gives thieves easier targets.
Having a bike that is not what thieves expect can help but can also hinder.
I fear less for 'I need a bike to get home' thieves with my recumbent bike, but more for thieves who steal on order. I will therefor not park my recumbent in the same location in a regular pattern, except at my work, so those thieves working on order will not know where to look for it. (At work it will be harder for them as the bikes are parked on own ground.)
I have never taken my seat/saddle off my bike, also as in my country nobody does for just parking and bikes without seats are seen as left behind and now donors of parts.