So i know that the Surface Pro X has 32-bit Emulation but in some articles and videos, people went over some apps crashing even though emulation of them should be possible. What about Lazarus? Is there someone who uses or at least tried to use Lazarus on Surface Pro X or Windows on ARM? Can and does it run with it and is the performance that worse?
i386 Lazarus works without any problems on Windows for ARM64.
Does anybody have already installed Windows 10 on a Rpi 3-B?
Not on a Pi 3B, but on a Pi 4 inside a VM.
And get fpc work on it?
The i386 one, yes (including Lazarus). The aarch64 still has some bugs and is not fully useable yet.
And are the binaries compiled on Windows-Rpi compatible with MS Surface Pro X?
It's simply the i386 compiler. It doesn't generate any different binaries than it would on a i386 system.