Nope. Seeing that FCM has GCM as its core, there is no limit in the number of Topics for any app. There used to be a 1 million limit, but it was removed. You can refer to this Google Developers Blog for that.
Also, when creating a Topic in FCM, it could take up to 24 hours for it to be show up in the Firebase Console, as per this post. Cheers! :D
与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…
