If you are trying to learn a new technology you should think of a project that applies that technology and that is useful to use that technology, the most important thing here is that it actually solves a real problem.
On the other hand if you want to do a project and not learn anything in particular, you should look for what technology solves better (better here is very debatable, maybe better for you is better developer experience or better performance, better UI, etc.) the different problems that you suppose you will have to reach your desired goal.
It depends on the problem side, let me explain:
If you are trying to learn a new technology you should think of a project that applies that technology and that is useful to use that technology, the most important thing here is that it actually solves a real problem.
On the other hand if you want to do a project and not learn anything in particular, you should look for what technology solves better (better here is very debatable, maybe better for you is better developer experience or better performance, better UI, etc.) the different problems that you suppose you will have to reach your desired goal.
Thanks for sharing your perspective - really important to reflect also what 'better' or ' more suitable' really means for each project!