Good advice! Playing slower time controls (rapid) and diligently checking on the safety of your pieces + how many times a square is defended before going to it, on every turn, will get you a long way in beginner chess. And speaking from experience it's only a headache to do it for a little while, soon enough it becomes automatic and takes a lot less time. Good habits are key!
For people wondering why they can't improve
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Improving Your Chess - Resources for Beginners and Beyond.....
https://www.chess.com/blog/RussBell/improving-your-chess-resources-for-beginners-and-beyond
https://www.chess.com/blog/RussBell
Take Avetik Grigoryan's skills course 'Blunderproof'. Seriously, it's reliably dropped my blunder rate from 10-11 to 2-3 per game.