I feel like they should be prioritizing stuff like a government and industry and tradesmen before whatever an adventure guild does. Like whatever they do, like hunting? Gathering resources? Guarding? might be done better, cheaper, and more efficient by the giant ants.
The ants can serve largely as soldiers for a standing army. Technically, an Adventurers Guild is a kind of industry in this kind of world setting. Government, this is a small village at the moment, just with a huge palace, so the scale of responsibilities of the MC are still at the range of a Chief or Mayor, but will expand with their growth. As the population increases, he can establish new offices, new positions, and recruit new personnel.
The Alibaba Trading Company at the moment, has a monopoly on the entire local market of their new country, so with careful management, their influence can explode. They export goods from the Sand Kingdom, import others, the presence of a Guild and amenities established by the trading company can attract smaller merchants, and adventurers. The presence of a growing population of adventurers and traders will entice other people and professions to settle there, like blacksmiths, artisans and jewelers for the precious stones they found, toolmakers, armorers, and the like, especially if they can guarantee security. It will require meticulous management, a lot of moxy, and skillful negotiations with other territories, but it can be done.
