New to eBikes - where to start?

Hey everyone!

I'm totally new to the eBike world and trying to figure out where to even begin. I'm leaning towards building my own conversion kit rather than buying a pre-built, mostly because I love tinkering and want to save some cash. My current ride is an older hardtail mountain bike that I use for commuting ~10 miles round trip on mostly paved paths, but I'd love to tackle some light trails too.

For those of you who've done a DIY conversion, what was your biggest learning curve or the one piece of advice you wish you knew before starting? I'm looking at hub motors vs. mid-drives and feeling a bit overwhelmed by all the options!