Workaround: to substack forcing new users to download their app
I tried to subscribe to my substack on my friend's phone. It redirected him to playstore to download app and also to create a substack account.
I felt like this would be a resistive step to people whom I share my substack post links and are not on substack to simply subscribe to my mailing list.
I just turned off the pledge options in settings. but it was still showing download substack app to complete subscription.
I opened options on browser and turned on desktop website option. and voila, the subscribe button directly adds their email to mailing list without all these redirects.