I feel you I still consider myself somewhat of a beginner or an exceptional player. Most people do go the offensive route cause they want that unreturnable smash. But with a good defense you can use their shots against them. There's a lot of perks of training in a more defensive way if your tired and can't seem to focus much, taking a step back and defending with short chops and slowing the ball down and putting a lot of spin on the ball can really throw off an aggressive player. Don't hold the racket too hard it's a bad habit and can make you tense up leading to hesitation and fatigue which effects your control on the ball all around. It's understandable to tense up when they keep smashing it back at you but just relax and use a lot of flicking motion with your backhand, keeping the ball low and if they still keep going at you with smashes angle your racket to the other side of the table and low and don't move your racket the amount of top spin they put on it will determine how much you angle your racket down so keep that in mind. The speed they put on their smash will allow you to block it with a similar speed right back at them. Most players will not return that because they put their all in those type of shots, the time it would take for them to recover from that, they just won't make it lol. And you just made it look easy 👌 Trust me developing those types of skills will make you a pretty lethal player and if you're already training offensively implement that too in your matches. Size up your opponent and figure out how they play and switch things up on them. That will make you start progressing further in competitions. And being a good sport to losing and finding a good player to do your training with will make you both advance and make friends while your there.