Smart tv apps tend to suck. Slow and buggy. I'd use a separate device. Then run hdmi direct from that to the tv and another line from the device to the receiver for audio. Though the best solution is a new receiver.
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Streaming Devices: Nvidia Shield TV, 2x Roku 3's, 1st and 2nd gen chromecast, Amazon Fire TV stick 2nd gen, Apple TV 4, xbox 360, xbox one
Displays: Vizio M602i-B3, LG OLED65B6, panasonic ax100u on a 145" S-I-L-V-E-R painted screen, 40" Samsung(don't recall model #)
Receivers: Denon X3300, Yamaha RX-V663. Bluray/UHD player: Oppo UDP-203
Retired - HTPC: Intel e6300 2.8ghz, Intel DG45ID, 2gb DDR2, Radeon 5570, MCE IR receiver