You can have a look at this module idle Session Time out , I haven’t tried it in PWA. You can give it a try.
Good Luck !!
if you have your app deployed on cloud or running locally, you can add the custom environment variable in the runtime customizations.
SessionTimeout : 6000 (1 minute)
see below screenshot for local
Also you can use the IdleSessionTimeOut module… idle time out
Have a look at the Session Timeout widget in the appstore.