opening is important even at 1700



Opening theory is not as important at your level- if you do study openings, don't study moves- study plans and ideas. You can study some concrete traps, but otherwise when your opponent gets out of theory, the player who studied plans instead of moves will have the advantage in the upcoming struggle.
https://www.chess.com/article/view/learning-an-opening-to-memorize-or-understand
https://www.chess.com/article/view/3-ways-to-learn-new-openings
https://www.chess.com/article/view/how-to-understand-openings
"... Overall, I would advise most players to stick to a fairly limited range of openings, and not to worry about learning too much by heart. ..." - FM Steve Giddins (2008)
"... I feel that the main reasons to buy an opening book are to give a good overview of the opening, and to explain general plans and ideas. ..." - GM John Nunn (2006)
"... If the book contains illustrative games, it is worth playing these over first ..." - GM John Nunn (2006)
"... the average player only needs to know a limited amount about the openings he plays. Providing he understands the main aims of the opening, a few typical plans and a handful of basic variations, that is enough. ..." - FM Steve Giddins (2008)
"... Everyman Chess has started a new series aimed at those who want to understand the basics of an opening, i.e., the not-yet-so-strong players. ... I imagine [there] will be a long series based on the premise of bringing the basic ideas of an opening to the reader through plenty of introductory text, game annotations, hints, plans and much more. ..." - FM Carsten Hansen (2002)
https://web.archive.org/web/20140627055734/http://www.chesscafe.com/text/hansen38.pdf
"The way I suggest you study this book is to play through the main games once, relatively quickly, and then start playing the variation in actual games. Playing an opening in real games is of vital importance - without this kind of live practice it is impossible to get a 'feel' for the kind of game it leads to. There is time enough later for involvement with the details, after playing your games it is good to look up the line." - GM Nigel Davies (2005)
"... Review each of your games, identifying opening (and other) mistakes with the goal of not repeatedly making the same mistake. ... It is especially critical not to continually fall into opening traps – or even lines that result in difficult positions ..." - NM Dan Heisman (2007)
https://web.archive.org/web/20140627062646/http://www.chesscafe.com/text/heisman81.pdf


I remember an interview with Bent Larsen when he was in the top 5 in the world. They asked him about preparing openings, and what he looked for when reviewing the games of his competitors. He said he looked for the ideas, and that memorizing moves without understanding ideas was a waste anyway, because you'd never be able to remember them (I'm paraphrasing of course).
All this to say: "understanding ideas and plans" isn't just recommended "at our level" it's recommended at every level. It's the whole point.
Maybe you already know this, but I'm just saying for OP's sake, or for someone else reading this. It's not as if GM sit around memorizing tons of moves... sure they do that too, but the main point is understanding.