Would a chopping block on that is fire safe work for you?
You could use the chopping block over the sink also to create more workspace or hide a messy sink.
You could cover it with a piece of plexiglass that is decorated with decals that complement the theme in your kitchen.
Sorry, I do not condone wood construction for this project, which is the common solution.
I would recommend buying a half sheet of venentucious tile backer board, called “Hardie backer”, by the trades.
Cut it to size, outside, with a mask & gloves.
Then thinset tile mosaics on it and grout it with non-sanded grout. Make a pattern if you want.
To build up the edge, I would Construction glue (Liquid Nails) 2x2’s around the perimeter and glue tiles on the edge & the bottom & grout them. If the inside edge of the wood is close to a burner, I would tile the insides too.
Get the measurements of the stovetop as well as the measurements for the entire stove space including gaps. These may be the same, but often are not. Go to a flooring store and ask to buy a floor sample the size of the stove space or stovetop. It should cost less than $10 for the sample. Never put it on a hot stove. It will be heavy. Where will you store it when you are using the stove? Don’t let children lift it or play on it. Best wishes, 🤶🏻