This could not be that difficult for the developers at Jagex
You will find several moneymaking approaches that OSRS gold tend to become eternal: Covering the always-extreme source for certain products, such as raw material collecting, to killing creatures of different strengths for infrequent drops, and then finally playing the marketplace by investing huge amounts of money to make larger sums of money. Of these, gathering raw materials is the cheapest but will require constant function. It is rewarding, but you are basically slaving away so other individuals reap the benefits.
Killing items is dangerous and contains a variable of reduction involved, but it is usually a hell of a lot more profitable than gathering raw materials. It may, however, need private skill, more understanding, high battle stats along with a group in some specific scenarios. Playing the market market requires knowledge, patience and a beginning lien of gold. Basically buy things for cheap, then purchase for a higher cost. The concept is simple, and while you need to keep a tab on the market frequently, it is probably the method that requires the least amount of”work”, however it will need you to be patient, make the proper choices rather than panic.
If I had been you, I’d take those 28 million and either invest in the Runescape 3 gold market if you know the way, or just to seriously work on your core battle stats and concentrate on killing things for loot. The drawback there is… the maximum reward drops usually requires stats way over yours, so you would need to seriously work on battle for a while.