What's a word or phrase for "a problem with multiple solutions"?

Consider the following situations:

A crossword puzzle where multiple word combinations satisfy the clues and fit the grid.

A mathematical problem where there are multiple ways to come to the correct answer (eg. the many ways to calculate pi)

You need to get from point A to point B and could drive, bicycle, take the bus, or walk.

You want something improved in your house and you speak to different professionals. The plumber recommends something with pipes; the carpenter, with wood; the electrician, with wires and circuits, etc.

In these situations, there are multiple ways to ultimately solve the issue, but each might have its advantages and disadvantages.

Is there a word or phrase describing these situations?

edit: My question is distinct from this question. The linked question seeks a word describing the solutions. I seek a word describing the problem.

I would call it an open-ended problem which is also defined as:

Open-ended problems are those which have many solutions or no solutions for the problem as defined.

by the University of Michigan website that accompanies the Third Edition of Strategies for Creative Problem Solving (by H. Scott Fogler and Steven E. LeBlanc with Benjamin Rizzo.)

The relevant sense of the adjective open-ended listed in the OED:

Admitting of several possible outcomes, conclusions, interpretations, etc.; allowing for future changes or additions. Also: having no predetermined limit or end; indefinite.

Multisolution is an adjective listed in Wiktionary but it is not a common word, defined as:

Having or pertaining to more than one solution.