Alright so for my own writing i did some research into room temperature superconductivity (Which i assume you mean here, there are plenty of superconductors, but non of them work in easy to maintain conditions. Most have to be very cold or under very high pressure).
To be blunt here, the impact of a cheap high critical current, room temperature superconductor cannot be understated. If we found such a material, there would be world peace, Russia would pull out of Ukraine, Israel and Palestine would sing and dance, the world would disarm, it would rain good feelings and hope and they would make a second season of "The Lost Room".
But why ?
First some terms. As you probably know, Superconductivity just means a material exabits zero electrical resistance. This is not a handwavy thing, 0 means 0. Superconductors have not resistance and don't lose current. There are experiments which have been going on for decades in which current is trapped in a loop of Superconducting wire. And there has been no lose in current.
The Critical Temperature refers to the temperature at which point a material becomes superconducting. Usually in a fairly dramatic and rapid way. The Critical Pressure is the same, just for pressure. For temperature, the higher the better, for pressure the lower the better. Finally, the Critical current is a bit abstract but basically refers to the maximum current you can send through a given radii of Superconducting wire before it stops being superconductive.
So an ideal RTS (Room Temperature Superconductor) is one that has a high Critical current, low critical pressure and high critical temperature.
So, if we had one what would change ?
Everything
Power Generation
With an RTS you could build Motors and Generators which achieve efficiencies of 90-98%. This is in part because you can use the magnetic properties of RTS to make frictionless shafts but also because there are just no internal loses. Most energy in power generation is wasted as Heat. This happens to either no or almost no extend with RTS.
Power Storage & Transport
If you have an RTS, you get to build Superconducting Magnetic Energy Storage batteries. Which are, simplified, loops of superconducting wire that store current. These batteries would not only store potentially orders of magnitude more energy than Lithium-Ion but may even surpass gasoline. To give a visual example, if phones had superconducting magnetic storage, you could charge an iPhone 14 in 1,4 seconds to full capacity. The phone would heat up ~20 Degrees though. Also these Batteries don't wear down. You can, in principle, have an infinite number of cycles. Of course other components wont like that but it is an advantage.
Of course, a cheap RTS also makes something like a Mag-Lev endlessly more practical as you don't need to cool them.
It should also be noted that if we had a RTS, it is likely we would transition our Grid to use DC instead of AC. AC is used because it is more efficient over long distance energy transport. But basically all electronic devices use DC. If you have an RTS, you don't need to use AC because the gird has no loses. DC also has some safety and practical advantages over AC.
Conventional Computing
While Transistors obviously need resistance to you know work, RTS would still enable massive gains. It is estimated you could build a Petaflop scale Supercomputer which uses only 2-5% the power of current such machines using RTS.
So RTS would allow us to build Supercomputers on the yottaFLOPS scale, which itself has such massive implications for the world you can (and people have) write entire papers on it. Anything from Weather simulations weeks into the future to a utter revolution in Medicine and data analysis.
Quantum Computing
A big issue with modern Quantum Computers is that making Qubits is a bit of a pain because they are often very bulky and have to be cooled. If you have RTS, you get to make "Magnetic Qubits" or MQ-Bits. These would be significantly smaller and make large scale Quantum Computers feasible. Which, as i am sure you know, would also be a rather significant revolution for any field that needs Simulations. Such as Physical, Biologicals or Neural research.
Green Technologies
Energy generation and renewables could just be the largest field for RTS. Obviously not having any transmission loses and super efficient generators is good. But RTS would also allow you to make super cheap desalination / Sea Water Purification plants. Which intern could spell the end for any Water crisis.
Photovoltaics could reach their theoretical limits with RTS, making panels which are 70% efficient, which intern would make any other form of power generation obsolete overnight.
So
This list goes on. The applications for RTS are endless and it is correctly identified as a magic material. If we had it, it would solve a lot of problems by default.
This being said, there is an issue. We have no theory for RTS. All we have are theories for high pressure or low temperature superconductors. We dont know how an RTS would work, or if it even can. The theory behind Superconductivity is itself not very well understood and a large part of the field is guessing. People just test random (ish) materials for Superconductivity. We have learned a lot and most experts believe there has to be an RTS. But from what i understand this is based on the apparent strangeness if there wasn't. Like, why would there be an arbitrary limit to Superconductivity ? We cannot really identify a clear reason why there should be a limit. One person in an interview i read said that if there is no RTS, that would be a bit like if there are only square continents. Like, why ?
So yeah, this is a bit long but i hope i could illustrate that a RTS would be beyond a major deal. The discovery of such a material would usher in a new era and you can bet all your live savings that Humanity, 100 years later, would splits its own history into "Pre" and "post Superconductivity". Everyone, and i mean everyone, on the planet would feel the impact of this. The closest thing you can compare it to is the discovery of electricity.