Depends on country, but this is a situation many were in when things tanked last year. Traded a bunch of crypto to crypto creating a bunch of taxable capital gains but never cashed anything out, and then comes tax time, market tanks, and you are holding coins that lost value but have a big tax bill.

If you end up in this situation, you either harvest the losses to claim against the gains (either in the same tax year or wait til next, sell and carry back). Or you hold and hope for gains that make the tax worth it.

If you just hold bags of shit and never sell, you'll pay tax on gains you never actually realized.

And yes you should get tax help.