Commonly, people think that QM is "statistical", "predicting only the probability of measuring observables". That one "cannot measure both position and momentum", has a "wave-particle " duality, cannot "choose one openning over another", that "all paths are valid", that is not understandble, and that "if you think you understand QM, then you don't understand it".

But nothing is mysterious, hidden, and as one studies it, all things are explained quantitatively and qualitatively. With time, there are no mysteries.

Bias and preconceptions make people think thar, as commonly said, "QM is wrong, I don't know how and why".

But QM is our most successful model of nature, and applies to all sciences, arts, and skills. Who does not use it, misses explanation power, insights, and correct explanations.

It is a regrettable loss, albeit all can be corrected.

That seems difficult to understand because it is false. The sooner you learn why and how, the better for you.

In particular, people clam to not understand the double-slit experiment. It is explained in:

https://www.researchgate.net/publication/370363989/

There are phenomena in the quantum realm which it is said don't have classical explanations based on some assumptions. For example tunneling. Here it is assumed the energy of the particle which is usable to pass a barrier is constant. While the total energy needs be constant, this energy can be oscillate in various forms for example as a vibrating spring or as ball bouncing from the floor. If this oscillation (frequency) is above our observation range, we can only see its average. Applying this to a bouncing ball where its energy flips repeatedly between kinetic and potential, I imagine such a ball running into a barrier higher than the average height of the bouncing ball. However the ball can bounce over the barrier as an everyday experience.

(Edit: This is an example how a object might penetrate an potential barrier clasically when required energy for this can be partially supplied by a mechanism which is sometimes not evident.)

Another example is directional quantization. When a spin 1/2 particle is subjected to an external field, it get aligned either in parallel or antiparallel. However an ordinary magnet cannot do this. Here is the assumption the magnet has a constant dipole like a permanent magnet. However, if it is a electromagnet driven by an AC signal with a DC bias, still we can observe a polarization in term of time average, but the AC field can cause the magnet spatially oscillate and this allows the electromagnet can find stable equilibrium both in parallel and antiparallel because it involve in parametric excitation, exactly of the Kapitza pendulum.

So one should not make assumptions while trying to prove a phenomenon can be exclusively modeled with QM.

HO: yes, there are phenomena in the quantum realm which simply don't have classical explanations -- try as one may, and that is why QM has to be used.

One example is stimulated emission. Another example is provided by the double-slit experiment. One cannot "pick and choose" controversially understood experiments.

On the other hand, there are phenomena in the classical realm which are controversial, until one finds a QM explanation. One example is called the "ultraviolet catastrophe".

Naivete. The biggest number to be quantum factored is 35, achieved on IBM’s Quantum Computer (https://arxiv.org/abs/1903.00768).

35 is a 6-bit number, so we are far away from 2048 bit RSA keys (which has 617 decimal digits – compared to these 2 digits!!!) In fact I’m sure most of you burst out laughing at this tiny number…