How to restructure campaigns without hurting sales?

You can create different portfolios and add specific campaigns to them.

If you want to change the campaign or ad group name then it’s impossible to do.

you can restructure campaigns by creating portfolios and adding campaigns to them, also if you have different ad groups you can change their names to set accordingly, you can also add new ad groups in campaigns or can split the keywords in 2 ad groups

You can make various portfolios and include particular campaigns in them.

well, I think portfolios are the best option but if you’re talking about sales you must have to do a bi-weekly analysis of your campaigns if you don’t want to restructure your campaigns simply do this and find out the least-performing keywords. Eliminate them or retarget them somewhere else.