What is your current setup where you are getting the 200ms lag? Are you connecting from the TV to some outboard speakers? You're not saying the TV speakers, themselves, are audio-delayed, are you?
If your TV is the only audio source (whether it's the built-in Roku or whatever else you're watching on it), you'll probably have to connect via HDMI-ARC. Otherwise, the TV would need an HDMI-OUT (doubtful) to connect to the AVR.
Also note that you're not going to get Dolby Digital PLUS (DD+) over optical. Optical just doesn't have the bandwidth for DD+ Some TVs will transcode DD+ to standard DD over optical out, but I wouldn't count on it. DD+ is the format used by Netflix, Amazon and others. You'd be stuck with regular stereo going the optical route from the TV to an AVR.
What is your issue with HDMI-ARC? I use it without any issues at all on my setup. I've got a Roku Premiere+, Apple TV, Chromecast, BluRay and Cable Box all connected via HDMI to my AVR. Then, I use the HDMI-ARC port on the AVR to connect to the HDMI-ARC jack on the TV. Works perfectly. The audio is coming from the devices, themselves (not the TV), but I do get my TV audio this way, as well, if I use the TV's smart apps like Netflix or Youtube or whatever other app is built in that I want to listen to on the AVR. In your case, the "device" is your TV.
Okay, so I'll try to explain this as best I can, but I usually over complicate everything.
The TV speakers ARE delayed, but only when those speakers are playing audio for an external device--in my case that's been Xbox One X, PS4 Pro, and a DirecTV Genie Mini. The delay is 200ms when set to Dolby Digital, DTS and 100ms when set to PCM. I can't verify the exact amount with DirecTV because there isn't a YouTube app or any kind of latency test.
When using the Roku TV YouTube channel to test delay, that seems to consistently be 0ms on the TV speakers. I don't have any other speakers to test with at the moment, but previously I was connecting various soundbars and there was always a delay. I don't remember if I got a number or it was just the "echo test", which is when I have the TV speakers and an external speaker both powered on and I can hear the TV speaker play first, followed by the external speaker.My current setup is exactly as follows:
(TV has 3 HDMI ports)HDMI ARC
has the Xbox One X connected via HDMI, with ARC disabled in the Roku TV's settings (I have tried enabling it as well).HDMI 2
has PS4 Pro connected via HDMI.HDMI 3
has a little HDMI switcher with a DirecTV Genie Mini and Nintendo Switch connected to it, though I've tried taking that out of the mix/disconnecting it entirely and it makes no difference, so I don't think it's an issue.
In a couple of hours, I'll have a Denon AVRS540BT and a pair of Polk T15 bookshelf speakers (and some speaker wire to figure out how to strip, I'm a first timer) at my house to attempt to bypass the TV's processing of the audio and hopefully solve this issue. I don't know if it works and I'm not 100% sure of the setup.
The AVR has 5 HDMI IN (3 of them 4K, so 2 of them are reserved for my Xbox One X and PS4 Pro), 1 HDMI-ARC OUT, and 2 Optical. I don't yet fully understand where the TV is getting connecting in all of this. HDMI IN and Optical, maybe? I guess I'll find out when it gets here, and of course I'll experiment to see what works and has the best results.
My hopes are that I can get rid of the audio delay and that I will have some good sound for my Roku TV and all connected devices.