me and my friend decided to split our work(apply metadata preset to lots of pictures) in half. So I am thinking that I will be doing half of it on my laptop and she will be doing hers on her laptop. But now the problem is, can this be done without sync on 2 devices with 1 account 1 subscription or allow sync without losing any preset data in an efficient way?
A single license allows you for non-concurrent use on 2 computer, i.e. your desktop and your laptop. Therefore, you can activate any 2 devices at anytime. If you sing out on one device, you can activate another (i.e. third device).
If the devices do not belong to you, this may conflict with the EULA - I'm not an expert regarding the EULA.
Another issue will be the data sync. Lightroom does not sync data between multiple computers (desktops, laptops). You need to establish some way to forward the catalog and the raw images, i.e. by using an external USB disk that you forward.
1 subscription across 2 different computers owned by 2 different people. Not legally.
As for what you are calling sync I have no idea what that means for you. LR is a single computer program not something that syncs across a network whether it is a LAN or WAN (Internet) easily and not natively.