On my LG C2 42 that I use for PC monitor I got tired of daily getting pop-ups for latest webos, so I listened to your advice and blocked the following domains on my Adguard DNS:
snu.lge.com
su.lge.com
su-d.lge.com
su-g.lge.com
s3-su-os-fw.s3.amazonaws.com
lgsmartad.com
snscu.lge.com
lgtvonline.lge.com
For adguard and few other DNS services when you create custom rules they needs to be in the following format :
||snu.lge.com^
Otherwise if not using DNS you can just block them in your main router's firewall custom rules.
Source: r/LGOLED · by /u/FuzzyAttitude_