Only the Pro has solvers and differential and integral functions. Solvers were sometimes not allowed in exams at my university.

The TI-30x Pro has a few more functions than the TI-30x PLus, e.g. num-solv. There is an overview list on the back of the packaging, but I no longer have it to hand. The manufacturer's website also has more information than digitec:
Look under Technical Data/Integrated Functions:
https://education.ti.com/de-ch...

https://education.ti.com/de-ch...

The Pro has a few more functions. These are not allowed at many secondary schools (e.g. solver for quadratic and cubic equations)

The TI-30X Pro can handle vectors, matrices, calculate integrals and derivatives of functions, solve equations and systems of equations, and find solutions to quadratic and cubic equations.
The TI-30 Plus does not have the listed capabilities