Thanks @justyy! I definitely agree about SQLite, originally Stratos was only going to have to handle things like NFTs and stuff so I was using SQLite because it is easier and there isn't much scalability requirements for just smaller NFTs.
Sequelize does work a lot like mongoose and it is more readable IMHO. I've already extracted the database logic into a specific module, database.js, though there is no need to have seperate code for SQLite and Sequelize as Sequelize supports SQLite already.