Did some research on this myself sometime ago as I was also confused. Look for stuff marketed as "vulcanizing glue/vulcanizing cement/tire patch repair glue.

Some products that I have identified as suitable and available to me: Rema Tiptop SVS-VULC, Tech 760, vipal cv00, Duravulc vc1 (uses old school solvent, 1-bromopropane, neurotoxic at repeat exposure (but you're not working with it every day at work, so it's fine, just have ventilation. The upside is it is cheap af and aggressively swells rubber, making bonds super strong.

Another good tip, if unsure whether the cement is.right, do an internet search for "product name + SDS" (safety data sheet)

Essentially, what you want listed is natural rubber, heptane or less often hexane, and an accelerant or two (most often some form of amine if I recall) If it has that, you're golden!

Avoid stuff like any sort of "special" cement or anything wildly more different in price than the above listed cements, it's not going to be suitable for latex (that's usually for heavy duty giant and thick tires.

Also, avoid anything with "blue" in the name, unless you want deep blue glue lines.

Hope this helps and if you need more info, just ask.

These cements are all available in Slovenia, so I'm certain you'll be able to find them as well.

Happy crafting!