Need upgrade from Denon 1520 and better DAC

SACDs.  You need a universal player/transport in your chain.  I would suggest a used Oppo 105 or 105D.  You don’t need all the video elements, but it has good two-channel DAC.  Can be had for under a grand. All needs in one box.  Another choice is used Arcam CDP or universal player that handle all three formats you suggest. Again, one box solutions, could find for less than $1k

playpen-

look into a Denon CD/SACD player if your enjoy its house sound.
Happy Listening!

Arcam CD37, CDS27 or UDP411.

Cambridge Audio universal player also possible choice.

Denon 3XXX or 5XXX universal players are a possible solution, although have not heard those in long time or compared to current or recent crop of uni players mentioned already. In any case older better Denons could at very least serve as solid universal transport matched with modern DAC.

Marantz SA8003