Which is better for a bright living room?

The LG G6. Its OLED evo panel is the brighter generation, and reviewers consistently rate G-series brightness above standard OLED sets. The Sony is fine in a dim room but gives up headroom in daylight.

Which has more ports for a console, soundbar and streaming box?

The LG. Its G series carries four HDMI 2.1 inputs, while the Sony listing shows only two HDMI ports. If you run a PS5, a soundbar and a streamer, the LG saves you a switcher.

Which is easier to wall mount?

The LG. It is about 1 inch deep with a published VESA 300 x 300 pattern, so it hangs nearly flush. The Sony listing gives no depth or bracket spec, so check before you buy a mount.

Is the LG worth stepping up to over the Sony?

For most buyers, yes. You get the brighter evo panel, four HDMI 2.1 ports and a flush gallery design. Step down to the Sony only if Sony's processing or its Siri support matters more to you.

Both are OLED and age similarly, with no burn-in difference published between them. The LG's four HDMI ports and published mount spec make it easier to live with long term; panel life depends on how you use it.

Do both support 4K at 120 Hz?

Yes. Both are 3840 x 2160 OLEDs with a 120 Hz native refresh rate, and the LG accepts input up to 165 Hz. Check that your console or PC cable supports the rate you want.

Sony K77XR80PAEP 77-inch TV vs LG G6 OLED evo 77" 4K Smart TV

Both are 77-inch 4K OLEDs at 120 Hz, so the picture basics match. The LG G6 is the stronger pick for most buyers: OLED evo panel, a gallery design that mounts nearly flush at about 1 inch deep, four HDMI inputs on the G-series, and a longer track record of praise for brightness and processing. The Sony XR80 is the step-down choice, and its listing here is thin on ports and panel detail, so confirm the exact connections before you commit.

Choose the Sony K77XR80PAEP if you want Sony's processing and Google TV with Google Assistant, Alexa and Siri support built in, and you do not need a flush wall mount.
Choose the LG OLED Evo G6 if you want the brighter OLED evo panel, a slim gallery-style set that sits almost flat to the wall, and the wider connectivity LG builds into its G series.

Prices

Sony K77XR80PAEP 77-inch TV: $2,299.99 at Schaefer's (last seen Nov 11)