OP posted a video (how to) READ THE SPIN ON A SERVE INSTANTLY
Personally i changed my approach to this and receiving a few months ago. I kinda give up on reading the spin on the serve INSTANTLY.
Instead I focus on how to make a good receive EVEN IF IM NOT SURE OF THE SPIN and ON TRYING TO GET AS MUCH INFO EVEN IF LATE.
Of course i watch the opponent serving and try to see the impact but ill be honest, more than 50% of the time, especially against the better players who have good serves, i don't see the impact, because the motion is too fast, i can't always see clearly if the racket angle is below the ball or above, and some servers are masters in disguise.
Instead i try to get partial info: if the impact was NOT FAST then there must not be a LOT of spin. If it is fast, higher chance of heavy backspin. Also i look if the ball has sidespin or reverse sidespin. Many opponents don't disguise the sidespin and we can tell already from the grip and think of which receive we can do and on which side to contact the ball.
Then i try to switch very quickly my attention from the opponents racket to the incoming ball, try to see where is the first bounce (don't always see it), and i must have totally be focused on the ball by the time its in my half where i MUST see the top of the bounce and trajectory to have the timing right, if the serve is short i have also a chance sometimes to pay attention at the ("Nittaku") mark on the ball to see whether the serve is spinny or no-spin/float.
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this is perhaps the most fundamental change and improvement in my game in the last months (/years ?).
I've removed the frustration of not being able to read the spin immediately
I've removed the urge to receive the ball too early without knowing whats coming to me.
One advice from a previous coach was to "stop-receive" on short serves by taking the ball early on the bounce. but you can't do that if you're not able to know if the serve was float / backspin (or topspin !)
I think it may be a good advice for those advanced players or at least those with high spin reading skills.
But I found out that having a more patient timing works out better for me, its safer, yes its demanding a different touch to play with a different timing. I would still do an aggressive-by the bounce- stop-receive only once in a while but would absolutely refrain from it in game1 or in deuce.
when the ball is long, no hesitation, i know i have to open the game with a loop. if its half long, im also trying most of the time to open with a chiquita (2/3 of table) or with FH. If i feel unsure or hesitant about my position or footwork, then i decide to have a reaction shot like a last split second push or fishing ball.
TLDR
don't try to READ THE SPIN INSTANTLY. Try to get as much information on the serve at all stages, from seeing the grip, to the last split second before you hit the ball. missing the information on the impact is forgivable.