I've heard about a bug, that actually breaks the system when no HDMI connection has been established. So it's definitely a good idea to try a different HDMI cable.
PS: Possible reason, why RPi OS boots: It doesn't use 4K resolution, but LE does. Make sure it's an HDMI 2.0 or 2.1 cable, if you connect it to a 4K TV.
Is the RPi2 Nightly build suitable for the RPi3 as well?
Yes.
Are you using HDMI-0 (next to USB-C) to connect to TV?
PS: You can post faster, but a mod (like me) has to check beginner posts before publishing.
OK, if you say so 
. Does any other OS (like RPi OS) boot?
Use Etcher to write the microSD.
Could you please direct me where to get the version. Thankyou very much
He already did. 
Thanks, those cables are OK. I think it could be a CEC driver problem on your NUC, and the planed USB-C adapter surely wont fix that.
Maybe we'll see what happed to the CEC driver then.
Are you using HDMI 2.0 or 2.1 cables to connect?
It's an HDMI 2.0 adapter, so it can deal with 10 bit HDR by standard definition.
I assume you only test with a computer monitor until you've been purchased the HDMI adapter. The computer monitor doesn't have CEC, which might be the reason of not loading the CEC driver. If the display supports CEC, then it's activated by default on LE.
Switch the video mode to always-on at Settings -> System -> Input -> Peripherals -> CEC Adapter.
Most add-on dev's are at the Kodi forum, so I'm not expecting much feedback here.
Because it's not a very popular lib, I suggest to compile it yourself. I think compiling on Raspberry Pi OS is the easiest, compared to cross-compiling on x86 PC.
PS: Use the 64 bit version of Raspberry Pi OS to be compatible to LE.
Is it still in-sync when switching off DRM Prime on LE 9.97.1?
HDMI mode settings have been moved from config.txt to cmdline.txt since LE 10.0 Beta. Maybe you've been tweaked the config.txt to make the 2012 TV work.
Did you had to do config.txt edits on former LE versions?
Thanks, I've been informed the dev's.
That's an interesting part of the log, when the stream stops:
2021-07-19 20:49:14.976 T:1370669952 DEBUG: CMMALPool::Configure pool:0x72454f50 960x540 (960x544) pix:-1 size:128 fmt:OPQV
2021-07-19 20:49:15.097 T:1379062656 DEBUG: Previous line repeats 5 times.
2021-07-19 20:49:15.097 T:1379062656 DEBUG: AddOnLog: InputStream Adaptive: Download http://127.0.0.1:52103/https://cmaf.lln.latam.hbomaxcdn.com/videos/GYGbVWwPkezzDwwEAAAGi/1/fd54c3/v/v4.mp4 finished, avg speed: 2533769.69byte/s, current speed: 2022153.00byte/s
2021-07-19 20:49:15.177 T:1370669952 DEBUG: CMMALPool::Configure pool:0x72454f50 960x540 (960x544) pix:-1 size:128 fmt:OPQV
2021-07-19 20:49:16.147 T:1343394688 DEBUG: Previous line repeats 30 times.
2021-07-19 20:49:16.147 T:1343394688 NOTICE: CVideoPlayerAudio::Process - stream stalled
2021-07-19 20:49:16.154 T:1415570304 DEBUG: CVideoPlayer::HandlePlaySpeed - audio stream stalled, triggering re-sync
2021-07-19 20:49:16.155 T:1415570304 DEBUG: CVideoPlayer::FlushBuffers - flushing buffers
2021-07-19 20:49:16.155 T:1343394688 DEBUG: CDVDAudio::Flush - flush audio stream
2021-07-19 20:49:16.156 T:1343394688 DEBUG: CDVDAudio::Pause - pausing audio stream
2021-07-19 20:49:16.156 T:1370669952 DEBUG: CMMALPool::Configure pool:0x72454f50 960x540 (960x544) pix:-1 size:128 fmt:OPQV
2021-07-19 20:49:16.168 T:1463673728 DEBUG: CVideoPlayerVideo - CDVDMsg::GENERAL_SYNCHRONIZE
2021-07-19 20:49:16.168 T:1343394688 DEBUG: CVideoPlayerAudio - CDVDMsg::GENERAL_SYNCHRONIZE
2021-07-19 20:49:16.169 T:1415570304 DEBUG: CVideoPlayer::SetCaching - caching state 2
2021-07-19 20:49:16.169 T:1415570304 DEBUG: CDVDClock::SetSpeedAdjust - adjusted:0.000000
2021-07-19 20:49:16.172 T:1463673728 INFO: CVideoPlayerVideo - Stillframe left, switching to normal playback
2021-07-19 20:49:16.172 T:1415570304 DEBUG: demuxer seek to: 31693.000000It seems like the "InputStream Adaptive" add-on can't deal with the A/V format. Maybe go to the Kodi forum, and ask the dev's of this add-on.
PS: I just want to be sure you did everything correctly before I'll send a hint to the dev's.