Can my glowforge plus cut 1/2" wood? I know my proof grade is about a 1/4" yes?

The “Thick” proofgrade is 1/4". The “Medium” one is 1/8"

I’ve cut 1/4" woods in the past. But as @Tom_A suggested, not all wood is the same. If you look at this post, I cut Yellowheart and Walnut.

But I tried cutting Purple Heart, and it did not go well.

You can try cutting 1/2", and you may find the right settings. But it may be easier to cut 2x 1/4" and stack them. I do that a lot with Baltic Birch plywood. I know I can cut 1/4", but it’s faster and easier for me to cut 2 x 1/8" layers and glue them together.