I know that it's possible to install sugarcube 2x into offline/local twine.
I want to install it to Twine 2 online, because the offline version doesn't seem to have a zoom function.
Not without making it available via a network you can reach, which I'd rather people not do (though, a local server would also work).
Have you considered using a local install of the browser-based version instead? While it's not advertised on the front page, the same browser-based version that's hosted on the site here is available for download from the repo's download page. It's the package that named twine_{version}.zip (e.g. as of this writing, the current build: twine_2.0.10.zip). Using that, the normal install instructions should work.
That will let you have your zoom and SugarCube 2 at the same time.
Comments
Have you considered using a local install of the browser-based version instead? While it's not advertised on the front page, the same browser-based version that's hosted on the site here is available for download from the repo's download page. It's the package that named twine_{version}.zip (e.g. as of this writing, the current build: twine_2.0.10.zip). Using that, the normal install instructions should work.
That will let you have your zoom and SugarCube 2 at the same time.