Since your steel frame looks a little wider than a standard door, you can find the right size among the sizes of sliding doors. Also, you can measure the dimensions of your door slave in advance to order a wooden door in the store later. As far as I know, at https://www.ukoakdoors.co.uk/internal-oak-doors, the manufacturers make wooden oak doors to order if you ask them about them. What's wrong with the current sliding doors? I think about making one for a pantry in an old village house. In my city house, all the doors are made in the Victorian style, made of solid oak. I like their quality, the smoothness of the movements of the good attachment. I'm just interested in your opinion.