Diamond 5 demotion

Currently plat one 81 lp. After I hit diamond 5 will I demote out if I lose enough? I read some were on reddit that diamond 5 is the most toxic rank in the game due to people aFK and not caring because you basically cannot get demoted from diamond 5 is this true? Cause after I hit diamond 5 I wanna stop the climb and just kinda chill there. I do know about decay. And is decay still a thing I thought only master and up players succumb to decay? I also read that some where. Thanks ahead for the answers