Can you put transformers in series to get higher voltage?
You may chain two transformers, and if both have a 1:10 ratio, then the combination has a 1:100 ratio.

But beware that each transformer winding has a maximum voltage that it can withstand. If you exceed it (too much), you will experience an electric breakdown that will destroy your transformer.

For example, you cannot use a 220V-12V transformer, with the 12V winding connected to 220V mains, to produce 4kV.