> I’m using sessions/cookies for keeping state and keeping the user logged in
Good. Sessions are the standard for a reason, and it's currently considered best practice. And if you've got a session ID, and your clients support cookies, then sure, use cookies for storing them.
> will using JWT (with the token stored in the cookie) to keep the user logged in instead of sessions/cookies make my application more secure
No. Probably less secure, although if you know what you're doing you can mitigate the issues. But certainly not more secure.
Good. Sessions are the standard for a reason, and it's currently considered best practice. And if you've got a session ID, and your clients support cookies, then sure, use cookies for storing them.
> will using JWT (with the token stored in the cookie) to keep the user logged in instead of sessions/cookies make my application more secure
No. Probably less secure, although if you know what you're doing you can mitigate the issues. But certainly not more secure.