MySQL DB design for very long growing row size
So the pieces are there, but not structured in a way for a database to quickly access the data you need, or to allow growth without major restructuring.
In your case the best way to do that is to arrange the data in a longer format instead of the wide format you have.  So instead of having each column represent an entity identifiable only through a metadata table, you will have a key identify each row and the information will be organized by that key/timestamp combination.  Not only will this allow your database to grow without issue, you can also add new entities through inserting rows, not rebuilding your main table.  It's also much faster for most queries.
After discussion in chat, this is the model I believe this is a good starting point for your data. (For anyone not familiar with ER Diagrams, I always recommend reading this first).

This may require some tweaks as you go along, but the general structure should be there.
Note: The current diagram allows the same ModelCode to be used with more than one Instrument.  This is useful if the code is easily understood to mean a certain type of model or prediction.  If that is the case, adding a ModelType entity to give additional meaning/integrity to ModelCode would be desirable.  But if you want ModelCode to be unique across all instruments, you would need to place an alternate key (unique constraint) on that column.