Cryptocurrencies/Do I have to fill out the RT panel even though I only had capital losses?

Yes, if the countervalue of your cryptocurrency portfolio has exceeded 51,645.69 euros for more than 7 continuous business days, you must fill out the RT panel even if there have been only capital losses. This filling out is instrumental in carrying forward capital losses, which can be used in subsequent years (within the fifth) to reduce any taxable capital gains you may realize