Hello, Taking a gap is absolutely as it is for an better option. Many are taking time off to prepare for GATE exam these days so it wont be added as a black mark in your career. But make sure to give your best in preparation itself and don't fret about the exam or results. Ask yourself whether you want to go on as such or take time to polish yourself for a higher purpose.With a gate qualification you can get into PSU and your previous academic profile will be given a lesser light.

Gate preparation requires you to be thorough with your subject and you should plan accordingly to accommodate everything you have studied in the 4 years in 7 to 8 months. Weigh your strengths and the mark weightage in exams and finish those subjects first.

Here is the link of GATE 2021 to get and overview for your attempt https://engineering.careers360.com/articles/gate

Best wishes.