you're right, most sources show they don't have it now, it's sold out, but I've found some where you can check it now

https://grenka.ua/127664/chetvertyj-put-vvedenie-v-chetvertuyu-politicheskuyu-teoriyu here you can buy it as far as I see (it's Ukrainian site, but you can contact and know about delivery)

https://royallib.com/book/dugin_aleksandr/chetvertaya_politicheskaya_teoriya.html - download?

https://coollib.net/b/198048/read - online reading?

https://www.combook.ru/product/10435070/ and here you can order and it will be reprinted for you for 8-10 days