Wow, look at those roots!

One option is not to repot at all, unless the medium has broken down. Dends
like to be pot bound.

If you must repot, remember that Dends don't like to have their roots
disturbed, but I can't see any choice in this case.

I would trim the roots way back and pot this in your medium of choice. Keep
the pot as small as you can.

HTH

Diana