The one-bar rest thing is an Engraving Option. Engraving Options > Rests > Multi-bar rests > Bar count for single bar rests > No bar count.
For the chords, in the part layout select the chords you don’t want to see and set their Hide property in the properties panel. Dorico should then consolidate those bars as multi-bar rests (assuming that’s what’s set at Layout Options > Players > Bar Rests and Multi-bar Rests). There are other ways to go about this, such as turning off chord symbols for that player and then using Chord Symbol Regions specifically where you want them, if it happens to be a player that doesn’t need to see all the chord symbols.
Generally speaking Dorico’s highly customisable. If you think something’s stupid, change the options. For that matter, make use of the Save As Default buttons in the bottom left corners of the options dialogs - chances are, if you don’t want one-bar rest counts in this project, you won’t want them in the next project either.