A return to Spira could happen in the future, as Tetsuya Nomura and Motomu Toriyama have discussed the possibility of a Final Fantasy X-3, but the project could only begin after the Final Fantasy 7 Remake series finished. FF7 is generally considered to be the most iconic and popular entry in the series, but FFX and its sequel aren't far behind.
FFX is set in the world of Spira, which is home to a colossal monster named Sin. The only way for Sin to be stopped is for a summoner to go on a pilgrimage across the world in order to unlock the power of the Final Aeon, which will kill Sin. The only problem is that Sin keeps returning every few years, so the cycle of bloodshed continues. FFX stars Tidus, a professional athlete from the era before Sin who is thrown into the future and learns of Spira's troubles. He teams up with Yuna, one of Final Fantasy X's summoners, on her pilgrimage, and her guardians, as they travel the land and witness the damage that Sin has caused.
Fans have speculated about a return to the world of FFX with a new entry for years, and comments made by two of the creators of the original game suggest that it may come to pass. Tetsuya Nomura and Motomu Toriyama told Famitsu (via Ryukutya2089 and translated into English by Siliconera), that a third entry in the series is possible, but it will have to wait until the FF7 Remake project is complete, as that's their main priority at the moment.
There technically is content available that is set after the events of FFX-2, in the form of a novel and an audio drama, but these received a polarizing response from the fans. The stories involve romantic troubles between Tidus and Yuna, along with the return of Sin, which wipes out the happy endings of both earlier games. This Chrono Cross-style approach wasn't popular with the fans, so it wouldn't be surprising if these extra stories were ignored in a full FFX-3 game.
The FFX fans of the world might be waiting a long time for a new entry in the series. FF7 Remake is being broken up into different games, and there is currently no word regarding how long its series will be, or how long it will take for them to be completed. Square Enix also has its hands full with the upcoming FF16 and new content for the increasingly popular FFXIV, to say nothing of potential remakes of FF8 and FF9 after the FF7 Remake series is completed. Spira is one of the most beloved settings of any Final Fantasy game, but it could take a while before fans can visit it again.
Source: Ryukutya2089 (via Siliconera)