Shall JWT expires in mobile apps?

There are several different ways to handle JWT expiration. First thing is to determine the value of your token. If you're using the token as a log-in to a game server, you might not be as worried about having a week-long expiration as you would for a banking app.

There are lots of ways to handle token expiration, but the most common I find below.

Automatic time-based expiration. This is a best practice, because a hijacked JWT will have less value. As you mention, logging the user out unexpectedly can be a poor experience, so one option are to include a "refresh" token, that can be exchanged once for a new, fresh, valid JWT token when the shorter-lived token expires. Refresh tokens have a longer lifetime, and may be bound to additional details such as a secure element on the device, or a policy such as in-session only (e.g. must obtain a new refresh token on app restart).

Policy-based revocation - instead of relying on a baked-in timeout, you can issue a revocation of the JWT. This relies on your services deciding when to revoke a login, and publishing the revocation somewhere it can be checked. This basically is what opaque tokens do, and thus you've just thrown away one of the advantages of JWT, but you can time out a session based on activity observed by your services.

Generally, these token management policies operate independently from the "remember me" function, which is usually a special "long-lived" (e.g. forever, 30 days, 90 days etc) token that is secured behind a secure element (e.g. fingerprint recognition, password etc) on the device that's used to obtain session tokens when a user starts a new app session.