1) Dragon 20 is Magic.  UNless you're using someone to Tank, they should be either Force or Magic, Spirit won't Crit.  I'm start by swapping Magnarr for Rathalos.  If you're using Duchess to tank, you probably don't need UDK.  Swapp UDK for Deliana, unless youre dying, but duchess revives.  Affinity matters, Blessings matter (use Brimstone).

Given the lack of lego books, I'd possibly lean towards achak over deliana. But, yes on swapping in rathalos, even unbooked he should be doing more than magnarr due to affinity. But as you yourself mentioned, OP - the solution to speeding things up is to just get books, masteries, and better artifacts.

Masteries. That's it. I forgot what it's called. 

I have tons of champs not geared. So the ones you suggest I put in may not have any gear. I'll have to check. I don't gear unless I'm gonna use them and they're updated max level sometimes. 

it's near impossible for me to get books except rare. For me. :(

Yeah. You need to get working on a CB team ASAP. Honestly that should be a higher priority for you than speeding up your dragon20 run. If you are reliably clearing it, you can just let the autobattles run overnight.

Clan Boss? Ok but no clue there. I can start a new thread. 

Clan boss no. I'm the only one doing it. 

You might want a new clan then.  Clan boss is crucial for game progression.    

I put in Rathalos and Deliana. I die now a lot. So I'm using my original team above. I never die on 20.