I was play solo like 7 day and I was like getting killed by nightmare Winter mostly I was died by craziest melee monster attack range and the other one was died by lagging (bad network while I’m stacking three group monster)
you could go to Options and change some of your settings to see if that helps with lag, and maybe try not to have Pack Size Maps with value over 120%?
if you are using Wizard or Rogue, getting Dodge up to 60% will help a lot. for Warrior, you can go either Dodge or Block 60%. this will help at lower levels. at higher levels, you want both Dodge & Block for even more defense. HP, Armor, Resistance, & Damage Reduction also work good on lower levels, but the higher the floors you go, you eventually get to a point any monster can one hit you, so eventually you switch from those to Dodge & Block, and Sanctuary if necessary.
increasing your movement, with Movement Speed, Teleport, Vault, or other ways to get out of the way of monsters attacks is good defense also.
lastly, the best Defense is a good Offense, so if the monster is dead, they can’t kill you!
also, try playing DQ offline, so you don’t have to worry about lag from an online connection. you only really need to be online with DQ to save your game on DQ Cloud, checking your Leader Boards, or playing in Battle Arena.
hope this helps.