PVR box has built in hard disk inside, so that's why when you fast forward, rewind, play a programme... It is almost instant and real-time, cuz the PVR box can just read/write the hard disk locally and need not depend on Internet.
Ultra Box fully relies on Internet for cloud PVR recordings, VOD streaming, 'Play from Start', and others.
So when you perform PVR functions (rewind, fast forward, play...), it will go through lots of complicated process on their streaming server part, network stuff and so on.
That's why all Ultra Box users now will experience such delay.
Even if your Internet speed is few Gbps, it doesn't matter. As long if it depends on Internet to load, such delays would occur for sure.
They can only reduce the delay time (as near instant as Netflix), but it won't be as real-time as what you experienced on PVR box that relies on built in hard disk.
Ultra Box do supports external hard disk by connecting it to its USB 3.0 port.
But Astro do not authorise Ultra Box users to connect external hard disk yet, because they say "it isn't ready for now, and we don't know when will that happen". That's it, no further comments.
If they allow its users to connect external hard disk, then you would enjoy the same instantaneous response as what you experience on PVR box.
Cuz right now, Astro put their main focus on cloud recording first.
Astro, as well as almost all satellite pay TV providers around the world, will continue to use Ku band frequency for satellite TV purposes, which operates in between 10.7-12.75GHz.
There is no alternative frequencies for that already. Throughout worldwide, frequencies lower than 10.7GHz are utilised for something else, including for military, government, and other communication stuff that general public may not aware of.
Whether is it "suitable or not suitable" in tropical country, that's not for us to decide, cuz other tropical countries are also using it, like Thailand, Indonesia, Philippines, and more.
Rain fade issue on Ku band is common for tropical countries, and it has always been like this since forever.
Although C band (3.4-4.2GHz) doesn't have rain fade issue like Ku band, there's a very little number of pay TV providers worldwide are using it due to its overall costs, practicality and many other technical factors, and Astro won't even think of using or migrating to that for its pay TV services, so do stop hoping for it, if you were.
C band is used for other more important and essential usages (e.g. distributing content, live feeds, data services, and more). Long story short, something that is more important than providing just a satellite pay TV service.
Plus, that C band satellite use is under pressure since many countries worldwide are already been or planning to use for 5G services as soon as in the next coming years. You can Google that for more info.
Therefore, whether you like it or not, Astro's satellite TV will continue to experience rain fade issue, now and forever. So there's no solution for that. Period.
I know about cloud storage stuff but I still think that the service for the cloud Astro is using still not good. I know the PVR use the HDD and the reason why the external drive to UBox is not implemented most likely due to copyright issue. This is the same reason why certain channel cannot be recorded because cloud storage is not something secure. The internal HDD in PVR is on proprietary format that cannot be just copied out.
On PVR, even if you are not recording, you can rewind a bit in case you missed something but now this is not possible with new box. This is a big minus for me but you can play from start
I could predict that if the broadband infra improved and ascessible to more rural area, more and more people will move to IPTV. The reason for lower band high cost is just that you can put less number of channel since not much of bandwidth when it comes to UHD bandwidth requirement.