If you can't find an official download link for Limon S2, don't panic. The open-source community has caught up:

LimonS2 | Khmer fonts — ​ពុម្ព​អក្សរ​ខ្មែរ

You select Limon S2, but typing "Soksan" gives you English "Soksan" instead of សុខសាន្ត. Solution: You need a Khmer Unicode keyboard driver. Go to Windows Settings > Time & Language > Language & Region > Add a language > Khmer. Once added, switch to the "Khmer Phonetic" or "Khmer Keyboard" before typing.