but does it mean that BTC is the only reliable crypto due to its decentralised system/setting?
This is disturbing for me because i invested in multiple crypto and looking forward to the bull season.
Perhaps i might need to sell off my altcoin and buy just BTC? or what do you think?
Have this in mind. If you sell your altcoins to buy bitcoin you wont regret, rather with time you will be happy you made that decision. But imagine you sell your Bitcoins to buy altcoins then you are opening your investment portfolio to a higher risk of failing. This is not just about decentralization only, Bitcoin has gained trust from investors over a decades now. It is one asset that is certain to appreciate over time regardless of the fluctuation in the short term.