All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
If the reality is what was mentioned that this word means 'Christ', then this is the belief of those who believe in the divinity of Jesus Christ (peace be upon him). There is no doubt that believing in the divinity of Jesus Christ is Kufr (disbelief), as Allah the Almighty says (what means): {They have certainly disbelieved who say that Allah is Christ, the son of Mary…} [Quran 05:17] But merely keeping that toy is not considered disbelief, and it is not obligatory to get rid of it. However, that word of Kufr (disbelief) which is on it must be removed. Al-Bukhari reported that 'Aaishah said that the Prophet never left in his house anything carrying crosses but he removed it.
What is meant by removal is obliterating, rubbing, or dyeing it in a way that makes the figure disappear, as mentioned by Al-Hafidh Ibn Hajar in Fat’h Al-Bari.
As for covering it with a sticker, it appears to us - and Allah knows best - that it is not sufficient because it can be removed for the slightest reason.
Allah knows best.