What is the nature of the solution to the $Schrodinger$ wave equation for multi-electron atoms? How is it handled?

The Bohr model of the atom is contradicted by

If the uncertainty in velocity is $\frac{1}{2m} \sqrt{\frac{h}{\pi}}$, then the ratio of uncertainty in position and momentum is (in $: 1$)

Assertion $(A)$: The probability of finding an electron in a small volume around a point $(x, y, z)$ at a distance $r$ from the nucleus is proportional to $\psi^2$.
Reason $(R)$: Subatomic particles possess both particle and wave nature.

Why was a change in the Bohr Model of atom required? Due to which important development$(s)$,was the concept of movement of an electron in an orbit replaced by the concept of probability of finding an electron in an orbital? What is the name given to the changed model of atom?

The uncertainty principle was enunciated by