To increase the session lifetime, simply increase the sessionTimeout property in the xs-app.json of your approuter.
https://www.npmjs.com/package/@sap/approuter#xs-appjson-configuration-file
xs-app.json
{
"welcomeFile": "index.html",
"authenticationMethod": "route",
"logout": {
"logoutEndpoint": "/do/logout"
},
"sessionTimeout": 60,
"routes": []
}