Polymorphic associations when you are not sure what the Datatype will be?

I am setting up a database for a CRM project. I’m trying to set-up polymorphic one-to-many associations with mySQL and Sequelize, following this tutorial, where the example is a Comment that can belong to an Image or a Video.

I have Reunions, Clients, Projects, Tasks, and possibly later other elements, where I want the user to be able to leave a Note, a Link, or a Document. I debated putting the Notes/Link/Document into one table but I think it might make it very chaotic and take a long time to filter?

The problem is our Clients and Projects have UUIDs for primary keys, but Tasks and Reunions have integers. From what I gather it’s not possible to have a column that accepts two types of Datatypes, so I’m thinking my options are:
– Change everything to have UUIDs
– Give an int ID number to the Clients and Projects
– Scratch everything because I am thinking about it wrong
– …???

Could you just point me in the right direction of what would be good practice in this case?

I am junior developer working with another junior on a huge project so we’re only slightly overwhelmed, ya kno

This is the first time I do something like this, so I am pretty sure I am missing a lot of elements moving forward.