Just bought a second unit tx3 s905x3 4gb 64gb recently.
Received on 15 Jan.
Tested working perfectly.

Ran a speed test on LAN connection.
Surprisingly it show 322mbps same speed as my fiber subscription.

I guess new tx3 upgraded to gigabit LAN

Link as below
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tx3 series, from older to newer:

tx3mini - uses amlogic s905w chipset, low end; 2+8, 2+16gb
tx3max - uses same as tx3mini but has bluetooth
tx3 s905x3, commonly now referred to as just tx3 - uses newer s905x3 chipset, 2+16, 4+32, 4+64gb
those live tv u require, they are not provided by the box or any box (u can try buying illegit ones/illegal, no discussion here).
the box is just a shell with hardware; everything needs an app or apk to do... u must install the right ones to do what u r looking for.
astrogo app will give astro channels, playtv@unifi will give those u mentioned - u need subscribers id/pw to get them to work.
these 2 apps require the box to be unrooted - tx3 series has a simple root switch, u just click to unroot.
youtube, kodi are generic - they will work on most/all boxes.

To shutdown I think better proper way i.e long press power button on remote you'll see small pop up on screen where you can select shutdown/restart/screenshot.

Or you can set power button to shutdown on single click, there is a setting on that on settings menu (powerkey definition).

What box that you have ? I have tx3 now, used to use tx3 mini.
Anyway you can use that shutdown button too.

I have same device as yours. Weird, never see hdr pop-up.

Check settings-droid settings-powerkey definition .. you can select shutdown for one click press on remote to shutdown the device.

this is weird.

unplug all cables, reconnect and try again.

it may be some CEC issue.

is tx3 directly connected to tv?

what else have u got connected to the TV?

yr troubles , i think, are due to yr assumptuon that yr mx3 remote can do same as orig remote.

NO... other than orig remote, any other remote will NOT be able to control ON/OFF, shutdown.

this applies to ALL boxes... unless u have the expertise to rekey, remap, reprogram some other remote control.

Sleep or standby, the clock n streaming works.

U may have not done yr initial settings properly.

My bad... i meant sleep or shutdown or unplug power, the clock comes on within seconds.

Go to settings, device preferences, date n time... set time zone to malaysia.

Cable or wifi?
ISP?
Speed?