Efficient use of Writer requires accepting its founding principles.
Every other text editor & code editor lets you indent or un-indent full paragraphs by using Tab or Shift+Tab. It’s as simple as that. You may think there’s a better way to do it, and that’s fine, you’re entitled to that opinion. But from a usability standpoint, you’re never going to convince me that it makes sense to have one software behave differently than literally every other text & code editor on every OS I’ve ever used. I go back & forth between Google Docs, VS Code, KWrite, & MSO frequently. All let you indent+un-indent this way. Only LO does not, which makes it cumbersome to switch back & forth.
You repeat all you want that LO’s way is right and every other application in existence is wrong, but even if that’s the case, norms matter, user experience matters, & your desired user experience is not the same as everyone’s, and it’s not what the vast majority of PC users are used to.