Subpod will be fine in a raised garden bed made from wood. Make sure you leave at least 2 cm/1 inch distance between the front of the Subpod and the garden bed wall.
To make the wood last longer, we have 2 recommendations:
Block the worm tea outlet (we use small craft supplies cork for this) or follow the instructions on how to plumb your Subpod to collect the liquid fertiliser/worm tea/juice: https://growhub.subpod.com/posts/how-is-the-subpod-plumbed-to-collect-worm-teajuice-how-do-we-get-the-worm-tea-from-the-subpod
Line the garden bed walls with landscape cloth or weed block prior to adding soil to avoid the wood having continual contact with the damp soil.