If optical works reliably, you could possibly leave both HDMI and optical plugged in to the sound bar. CEC volume control and power seems to still work with my sound bar when set to the optical input.
My setup currently has an audio drop out every few minutes. It seems to happen over both ARC and optical, though, so it's presumably just the Nvidia Shield being buggy. The UI bugs out too lately. I've had various forms of audio drop outs on that TV since at least 2020. It could be the TV corrupting the passthrough I guess. I'm not going to buy a whole new TV just to test that hypothesis.
My setup currently has an audio drop out every few minutes. It seems to happen over both ARC and optical, though, so it's presumably just the Nvidia Shield being buggy. The UI bugs out too lately. I've had various forms of audio drop outs on that TV since at least 2020. It could be the TV corrupting the passthrough I guess. I'm not going to buy a whole new TV just to test that hypothesis.