Nobody stopped and you can hold as much as you can. Holding stable coins won't make you profitable but if you are asking for Bitcoin, it is certainly of a better position and market gaining potential. I was planning it though but can't imagine the volatility and it holds me of not doing. But if you are committed to makes such long-term holding, then it's up to you. But couldn't think the safety assurance and I am afraid you'll be targeted by scammers. If you are holding that huge amount, I suggest not to use only one wallet, better to spread and so it keep unnoticed by scammers. This is the risk of holding a huge amount online.