They are most likely not a classic operator, as they don't have own antennas. However I believe they operate their own backend infrastructure, maybe even operate own exit points to the internet in various geographic regions. I just found a press release from 2023 where they state to have received 60 Mio USD in funding from major operators like Telefonica, Orange, Liberty Global. They must be doing more than just operate a website with that money. In the release they describe themselves as a marketplace for esims, I believe that's a bit of an understatement. From my perspective most of those esims they sell are own products with arbitary brands. The only exception I noticed was the dtac tourist sim for Thailand.