So today I played a guy who pushes against me a lot and I performed badly. I really struggle with the short game.
Don't sweat the short game right now, even many advanced players still struggle with a short game. It is a good idea to start training it though, you would learn a lot about touch and impact dynamics that would carry you through levels easier and you would have a usable weapon at the advanced level if you get there, wheras someone not training that would not have such a weapon.
it is better for you at this point to worry about reading the ball, its arrival time, the spot it will bounce... better to focus on perceiving that better... then stepping to the ball and taking it off the bounce with a loose grip and a very tiny jab real loose.
I'm not sure how I would return an underspin ball with no spin.
I explained it in a previous reply. It is a matter of loosening the grip DURING impact (to absorb the spin energy) and going through the ball without accelerating. The end result is that you "ate" the spin, gave back some pace, but very little spin with a stroke that looks just like a normal push stroke. That will mess up many a player to give you chances to attack if you are ready, decisive enough, and in position
For sidespin, I guess I would just angle my racket diagonally while sweeping it upwards under the ball?
You would have to get the tip down or up. Impacting ball on the side of the spin axis a little is an EASY way to overcome incoming spin and put your spin on the ball. It is my preferred way to handle incoming topspin. Think of why that is called a HOOKSHOT.
I'm always afraid to try to kill a high push, because it usually goes into the net when I try.
There are a few ways to loop, loopdrive, loopkill, or smash a high underspin ball. Mostly players loopkill or smash these. It really isn't too difficult to understand. You get into position, open the blade face (think perpendicular to table surface, accelerate the bat FORWARD, and follow through forward and upwards... more upwards for heavier incoming spin. If you cannot generate a very fast bat speed, this will still be a fail, a much worse fail than before. If you can get the angle and follow through properly, it is SO DAMN EASY to kill a high underspin ball you will get real pissed off you never learned it before.
The other way to kill a high underspin with just your lower arm swing and not so fast a stroke is to FIRM UP the grip real quickly real strong RIGHT AT IMPACT and go through the ball with same concept, forward, follow through more upward vs heavier ball. The firming up of the grip will eat the spin and transfer MAXIMUM energy to the ball, thus you can get away with just a lower arm swing. You will not produce a rocket ball, but so close to the table or over it, you do not need but 50% of the possible power to get the ball by opponent if they are at or near the table.
I'm not sure how I would push if my racket is facing downwards? Do you mean more vertically? The coach was telling me to have my racket almost horizontal on pushes. He said if I have it more vertical then the ball will likely go into the net.
If you open your bat way too much like that and impact the underspin ball on a low energy push shot, there is a good chance the ball will not even make it halfway to the net.
However, on a high energy shot or a shot where there is a big time firming of grip right at impact, the ball come off the bat differently. That is why you see such forward looking swings vs chopped balls by pros who seem to be taking it on the rise with an open bat and a big time forward swing. The ball comes off bat differently as the ball already has a lot of vertical energy you do not need to fight against, all you need is forward energy and a "catch and grab" on the ball with a very fast bat. This kind of stuff sounds counter-intuitive, but it is how the ball comes off the bat in that situation. If you strike the ball at a different part of the arc, then you need to impact it with a different swing plane and impact. it is confusing that that also has a different way it comes off the bat, but that is the under-discussed mystery of table tennis. Advanced players do this without realizing WHY if they learned as kids - you have a different path to neuron association as a kid.