I've been in 2 top tier school teams in Singapore and the UK (Maris Stella High in SG, multiple times national champion and Uni of Nottingham, reigning BUCS champions), both of which have national level head coaches (ex-singaporean womens national coach, Chen Wei, and Alan Cooke, present England coach), and both of which takes up most of my free time.
There is a reason why Asians are ahead and dominating this sports.
Lets start with my training regiment back in SG.
2x4hr+2x6hr sessions per week
Day one of 4hr:
30 mins service practice, 2hr exercise (more focused on a single stroke than western routines, ill get to that later), 1hr match play (top table or coach appointed opponents), 30 mins physicals that include frog leaps (8x100m).
Day two of 4hr
Service changed to Multiball.
6hr training will see both service and multiball practices, both 1 hr.
Now for the training in the UK.
Training sessions available to 1st team players (averagely ranked 21 in England)
2x2hr+1x3hr+1hr 1-2-1 with a current England national player
Every session is basically 30 mins warmup, 1hr matchplay and exercise routines for the rest of the time.
There arent multiballs (except for those 1-2-1) or service practices.
Almost no physicals too, much less those hellish frog leaps.
The major difference i feel comes from the exercise routines.
Western ones consist of a plethora of different shots, like the famous Falkenburg.
And the ones we did in Singapore would consist of a single shot. Like if we are practicing short pushes today, we will be doing short pushes until we reach the number of rallies the coach sets (200 is the usual for easier ones like pushing and hitting, harder ones will be like 30 consecutive forehand topspins, so if you drop one, you start from 0 again)
Personally, I think the latter works much better when Im trying to tune up my technique.
It's probably worth mentioning the Singapore interschool scene is MUCH more competitive than the UK.
I mean, these sort of things happen in a secondary school league (half the players in there are my juniors from Maris Stella High/Primary).
Also, the team in Green (and black in the background) is Raffles Instituition, the absolute best middle/high school in the country in terms of both academics and sports. This means that on top of being top notch in Table tennis, those guys are some of the brightest/hardworking students around too.