Up today (April 2025) this topic has been read 29.000 times, which is a quite big number and reflects the sheer number of users affected by this issue.
Another big number is the people of people where Spanish and Portuguese are official languages, that is about 700 million people. Combined, they constitute the second most spoken language in the globe, only behind modern standard Mandarin.
With a few minor exceptions, all these people use the two-surname system repeatedly explained in other posts. You can confirm this by googling for images of identity cards.
The fact is that Spanish and Portuguese people are reticent to use any ancestry software, including Ancestris, precisely because currently available software ignores the most fundamental mechanism of Spanish/Portuguese naming and, by extent, genealogy.
I would like to encourage the technical people at Ancestris, that so generously give their time and expertise developing this software, to develop the appropriate tools or even a new, open addendum to GEDCOM standard to solve this issue. It is far from easy, due in part to the strong path-dependency imposed by GEDCOM. But think in the rewards of such effort!
Thank you for your attention and thanks for the really good software that is Ancestris.