Replacing home cinema TV and amp, surround questions

[[GSV]Lemming]

Boredom in lockdown is a terrible thing so the house is getting all sorts of attention. The next project is a revamp of the lounge movie setup, still on a budget though.
I am looking at a 60" LG TV, with hdmi-arc for a little future proofing, and a new av amp, onkyo tx-sr393,
to connect my BD player, 4k fire tv box and very occasional console to.
The existing 50" TV will be used elsewhere, my pioneer vsx 1014 amp is being retired.
I don't use free view, no aerial connection in lounge, so most of the time it's the fire tv on plex, prime or Disney +. I already have 5.1 speakers, monitor audio, and a big subwoofer.

I want to ensure a good 5.1 sound signal, is the fire tv via hdmi going to be suitable for this? Will it pass through surround audio signals from plex, prime and catchup apps?

I was never truly happy with audio pass through from the TV to pioneer amp in the past, it never compared to the sound from my BD player.

Any comments or questions that can give me reassurance before I go spending?

 

[[GSV]Lemming]

The BD player was connected by hdmi to the TV, and optical to the amp. I had no hdmi on the amp for pass through so all sources went via the TV with fire tv audio the most disappointing.

I plan to have all sources connect to the amp via hdmi this time around, the TV itself will not act as a source for any audio as I have no free view connection.

I always suspected the fire tv to TV to amp connection was giving me a poor experience although I was unable to quantify it, the mere fact the BD connection was so much better seemed to prove it.
I wanted to ensure an arc connection just in case I get free view on the TV at some point, its placement on a freestanding fireplace in the middle of a large lounge-diner makes it unlikely at this point. No way to get a cable to it without being unsightly..

I cant say I miss live TV much, so little I am interested in and its always there on catchup if I can be bothered.

Thanks for the response, it gives me an expectation that this will be a decent improvement.