I’m getting. 4k tv. For Astro Ultra Box, do I have to get HMDI 2.0 cable to watch the UHD channel?

If they change your account type from Satellite to Plug & Play, it will trigger re-contract on their system.

Keep things simple.
Just perform Restore Factory Settings, and then select Plug & Play.
Leave your account type as Satellite. No harm one.

You can update your account service address through My Astro.

In the future, let's say you wanna watch Astro via satellite again, so you perform Restore Factory Settings and select Satellite, then you might see the "SIM Card Error" or "We apologise for the service interruption" message. That's what will happen when your Astro box isn't connected to the satellite signal for more than few weeks. The simple fix for this is, just refresh your smart card, then you can watch your channels as usual via satellite already.

Maybe try like this:
You inform Astro that you've hired own contractor to dismantle the dish and everything already installed at your new address.
So on Astro's end, they don't need to get a technician to come over and do this and that whatsoever.
All they need to do is just update the installation address and billing address in their system to your new home address, for record purposes.
That way, I don't think it will trigger recontract whatsoever.

Try clear NVRAM first
https://support.astro.com.my/question/refre...-ultra-ulti-box

If issue persists, contact customer service and ask them to get a technician to come over and check. From there, they'll likely just swap new box for you.
Their new Ultra boxes are working fine, so no need to worry too much there. If it's problematic, you would have see us complaining here

Ultra Box is covered with manufacturer warranty for 2 years (if not mistaken), and it starts from the day you firstly use the Ultra Box.
After the 2 years, any technical issues arises will be under after sales support, not under manufacturer warranty.
If your Astro subscription has ongoing contract, then after sales support services like satellite signal issue or box replacement, should be FOC.

But for retention discount.... Hmm I don't think it's counted?
What pack are you currently on, and what's the retention offer that you've accepted earlier on?