Matthew Barnicoat

Hi, I purchased a variety of coins in 2020, they subsequently all crashed in value, although staked etc. Now they are going up in value and I hope to sell in the coming months for profit. I made no gains in the interveneing 3 and a half years should I have filed tax returns each year? Or only once the assets are disposed off to report any capital gains Tax due. Also would the rate be the current CGT rate or the rate when purchased? Thanks