It has enough space, it´s almost empty and I can install other apps without any problem. Other people also tried in other tablets same brand and version and same problem happens.
The project is being developed for a public education institution. It will be deployed on thousands of those tablets, so manually updating to webview 71 with the webview´s apk is not an option for them. Here´s the message i am getting after it gets stuck for like 15 minutes trying to install. It is in spanish but translation is "WebView for Android System couldn´t be downloaded, try again and if it keeps not working, check for common ways to solve the issue". I´ve tried several times, also sent a comment, sufred the net, but couldn´t find a way. It is a very big project and I´ve bet on C3 and not C2 for it´s performance. There may be a way to disable webAssembly or to force webview update from some cordova plugin?