I'm on my second LG TV and have become wearily familiar with their hdmi antics. In my case it's compounded by three HUMAX boxes of different ages, two of which share the same remote IR 'channel' (which can't be changed). So switching one on switches the other on - or off. The TVs autosense then changes the input to the box I don't want on.

With my old (pre-smart) TV one of those boxes gave HDCP errors which I suspected was due to incompatibility between the TV and the box's hdmi versions. Maybe that's the problem with your bluray player - that will certainly involve HDCP.

I bought an hdmi ARC extractor to get the audio into an audio amp, but failed completely. Whether that's the TV or the ARC extractor I don't know. ARC seems to be aimed at soundbars - I don't have one - and nothing else.

Basically I think it's just badly implemented - whether that's the hardware or microcode I don't know - I suspect the latter the case of my WebOS TV.

I tried to get a TV with 4 or more hdmi sockets, but there are none. It needs an 'hdmi port replicator' like laptops have.