Why do you want to register for GST?
Trade volume over 20L will definitely attract GST.
When I asked about opening a current account for crypto trading they said you need to have GST tin number for having current account so literally you cannot open current account in India for crypto trading and also RBI said your account will be blocked if you are using it for buying or selling cryptos.
You must get current a/c without GST number. Not every business do 20L+ volume in a year.