In the supermarket pest control isle they have different products for different pests so bound to find something.

We don’t get silverfish but l would get an expert’s opinion.

I have no experience with silverfish. I suggest you talk to a pest control company for advice.

I would talk to a pest inspector if you have no luck.

Diatomaceous earth. Works well on all sorts of bugs. I use it for earwigs.

I have never heard of silverfish before so had a look on google.
It says they love the high humidity so the best way to prevent is to control the humidity in the home.
It also says that no home remedies have been proven to actually kill the infestation only the insect, you would have to get someone trained in to kill the insect and their eggs.
good luck hope its not to expensive to get someone in.