Sequelize is full blown ORM forcing you to hide SQL behind object representation. Knex is plain query builder, which is way too low level tool for application development.
Better to use objection.js it combines good parts of ORMs without compromising power of writing any kind of SQL queries.
Here is good article about it from the author of objection.js https://www.jakso.me/blog/objection-to-orm-hatred
Disclaimer: I’m knex maintainer and been also involved in development of objection.js.