Salted Capers - Salt Crystals Don't Dissolve

I don't think this is going to work, attempting to dry salt cure a previously brined product. It's soaked in liquid.

The traditional way of making the pictured product is to pick the capers fresh, sprinkle salt over them and periodically dump out any resultant liquid and add more salt until the capers stop giving off liquid (about a week).

Here's someone's instructions:

https://italian-connection.com/living-in-italy/italian-food-traditions-preserve-capers-in-salt/

Because the salt is sprinkled on fresh capers, you're only removing the water that's naturally present in the capers. This isn't unique to capers.

The same basic process is used to salt-cure olives:

https://www.thespruceeats.com/dry-salt-cured-olives-1327914

Note that this technique is probably thousands of years old. You don't brine the capers with vinegar then try to salt them. You just salt them from the start.

That's how the capers in this jar were made.

Scottolotto -
Yes, the jar of salted capers in your link is VERY expensive. 2x to 4x (per 100ml or 100g) the cost of similar salted capers, on sale here in Canada.

Sourcing alternatives for you:
1) Make them yourself by buying or growing raw capers, then packing in good kosher salt or sea salt to preserve them. But I think availability may be limited, and gardening obviously dependent on climate, how much time you want to give to it, etc.
2) I remember learning that there are a fair number of Italian immigrants and their descendants in Australia. Maybe search for a more affordable jar of salted capers at an Italian specialty shop (bricks and mortar or online or both).
3) Another possible source is Italian restauranteurs and their supply houses.
* They may be willing to sell to a civilian, as it were.
* The package size may be larger than you anticipated, but you may be able to use them up over their long 2-year shelf life in the fridge.
* Or split a package with one or two other households to make it worthwhile.