Bosnia And Herzegovina - Republic Of Srpska Sheets

My wife and I traveled in Republika Srpska in the spring of 2023 and found it very interesting -- I was surprised at how pro-Russian it was, we ate in one restaurant with two photos of Putin on the wall and we saw graffiti for the Wagner Group (this was before the Wagner Group's subsequent unsuccessful rebellion).

In any event, I've gotten interested in the stamps of the Serbian administration of Bosnia, but I've found it slow going. This is in part because I have a strong preference for postally used stamps.

Does any know of a source for kiloware or assortments of postally used Republika Srpska stamps? I've looked on ebay, HipStamp, PostBeeld, Stamporama, and Nordfrim with no luck. Mint stamps are available occasional, but not large quantities of postally used.

I'd also be interested in postally used stamps from the Croat administration of Bosnia.

Thanks in advance for any assistance anyone can provide.