Hi @vamsi.k,
Thank you for joining the Auth0 Community!
Regarding your question, Solution 2 seems more appropriate: use LogoutAsync before calling LoginAsync when the app is reinstalled.
Actually, it forces login after reinstallation, which is what you mention as Solution 1 
Anyway, the logout popup, is an issue I already submitted to our SDK team (see here). I will update this thread as soon as I get an answer.