Regarding diode laser power...make sure you research that thoroughly. You need to make sure the output laser power is sufficient. You might read "20W" on a laser module, but its optical output power (actual engraving/cutting power) might just be 5W. There are some diode lasers that use multiple source lasers, say all 5W, and use mirrors and prisms to combine them into a more powerful beam. Usually these are rated as the simple sum of the source lasers, so a 20W output power diode laser might have four different 5W internal lasers. I am not entirely certain that the combined power is 100% efficient, though, and I suspect the actual output optical power is less than the raw sum.
A lot of lasers are sold with their input power rating, rather than clearly stating their output power rating. Just make sure you can find and truly know what the output optical laser power is. A 5W output is good enough to burn some things into wood, but it may not be enough to do much more than that simple task. Further, a 5W laser will do that quite slowly. Cutting gets even slower.
Another point to consider. I've recently discovered that a lower powered laser is basically not really capable of engraving resins. Some, solid colors (notably black) might be possible. But mostly, a lower powered laser just melts the resin in place. If you need to engrave resins, you'll definitely want to find a more powerful laser module.