Legal regulations for eBikes

Hey everyone,

Been lurking for a bit, figured it's time to jump in! I'm planning a pretty ambitious custom build for a fat-tire eMTB – thinking a mid-drive Bafang setup on a custom frame. My main concern, especially with the higher power I'm aiming for, is navigating the legal landscape. How do you guys handle regulations like wattage limits or speed cut-offs when you're building something from scratch? Are there any specific things I should be aware of, especially since it's not a pre-built Class 1/2/3?