When you get into custom code development, Webflow's custom code character limit is a pain for a lot of people to work around.
However it need not be a barrier, no matter how much code you want to write.
Write and debug your code using a 3rd party programming tool like CodePen.io Pro or CodeSandbox. This will allow you to edit your code freely and simply refresh your published site to test it out.
Once your code is ready to go live, it's best to put it in a safer place like Github with JSDeliver as a CDN. This allows you to safeguard your code, and deliver it very quickly.