I feel. Dream defender is a pain in the ass. But if it makes it any more palatable for you, all you need to do is grind up to as high a stage as you can, let's say stage 30, and from that point just clear a single stage, 30 to 31 in this case, to get your full(in this case, 30 coins) reward. And you can keep doing that day after day, for all of your runs, until you're strong enough to continue pushing up through the stages.
Also, if you hate dream defender then you're gonna love arcana's spirit savior daily.
do keep in mind however the 1 handed + shield is dependent on the fact you can and will get a good shield. if you are in reboot, you would need 20 star to get use of the shield.
as far as shield vs medallion, both trigger shield mastery but yeah shield would be better of the 2 should you go with 1 handed sword and a shield
Paladin is different, I'm reading 2 handed is actually best