Launched in the year 2021, the 65GFU8990 is a 65" 4K TV from Grundig. It features a 10-bit IPS panel. The maximum resolution it can achieve is 3840 x 2160 with a refresh rate of 60 Hz and a pixel density of 68 ppi.
Picture Quality
After screen size and resolution, the next important feature of a display is its Color Reproduction Accuracy (defined by its color gamut specification).
This TV doesn't provide a color gamut specification, but don't worry, we have other means to guess that.
Now, since the TV features a big 65 inch screen, it won't come with a cheap panel, so here we can assume its equivalent sRGB coverage to be 90-100% or above. Undoubtedly The color quality on this TV should be Lifelike! It is capable of producing accurate colors.
Understanding Color Gamut
Color gamut spec of a TV is the measurement of the range of colors that the TV can produce.
In other words, this specification determines the ability of a display to produce accurate colors. A TV with low color gamut coverage will miss out on some colors (such as deep red), so the image produced will look "washed out" in colors.
It is specified in different units - sRGB,sRGB (standard RGB), NTSC 1953, DCI P3 to name a few.
But you don't need to worry about that, below is a chart that you can use to choose a TV with good color accuracy.
Now, after color gamut, the static contrast of a TV similarly impacts its picture quality.
Understanding the static contrast ratio
Static contrast ratio of a TV corresponds to its Black levels. A Display with low static contrast ratio (<1000:1) will not produce deep blacks. Moreover, such displays often suffer from backlight bleeds such as below:

This will affect your viewing experience considerably, especially in a dark room.
Like resolution, the static contrast ratio is also equally responsible for details. To put it into perspective, a TV with low contrast ratio will produce less shades of colors, thus lesser detail overall.
If given a choice, I will prefer a FHD TV with high contrast ratio over a 4K TV with low contrast ratio.
This TV comes with a static contrast ratio of 8000:1., well enough to produce deep blacks. The panel comes with local dimming feature which is a plus.
HDR and HLG (Hybrid Log Gamma) are also supported on this TV, so that's a plus.
As for brightness, it can go as bright as 250 nits. The backlight used on the panel is Direct LED.
Gaming Performance
If you are not planning to game on this TV, you can ignore these specs. But if you are also planning to use the TV for playing games or use it as a PC monitor, you would want to get a TV with the lowest input lag and response time.
Sadly, there is no specification for input lag on this TV. Now, as this is not a cheap TV from Grundig, we can expect an input lag of less than 20ms.
What is Input lag ?
This lag is the amount of time at which your inputs changes the content of the TV. Though, this won't matter much if you aren't into competitive/FPS games like call of duty.
But ideally, get a TV that has an input lag and response time of < 20ms.
Dimensions and Ergonomics
Vertically, the TV measures 65 inches and horizontally 57.24 inches.
In terms of thickness, it is 2.76 inches thick.
Overall it weighs approximately 19.35 Kgs including stand. Without stand, it weighs 16.85 Kilograms. So plan your space accordingly.
Coming to ergonomics — If you plan to wall mount the TV, you can make use of the VESA mount provided with this TV, which by the way has an interface size of 400 x 400 mm. However, there is no Swivel, Tilt or Pivot feature support in this TV.
Hardware and Audio
The chipset of this TV is powered by a 4-Core CPU. There is no mention on the total available RAM on the TV's official specsheet.
Speaking of OS, the Grundig 65GFU8990 runs Android TV Operating System.
For display connectivity, there are three HDMI 2.0 ports on this TV.
For connecting USB devices, you will have two USB 2.0 ports. Other connectivity ports include — 1x Satellite In (F-type), 1x Antenna (RF), 1x CI+ 1.3 and 1x Ethernet RJ45.
Regarding wireless connectivity, the manufacturer has provided Wi-Fi (2.5Ghz only) and Bluetooth.
The Audio unit of this TV is powered by 2 x 10W speakers.
Now, coming to power consumption, the TV consumes 114.24 Watts on average and 0.45 Watts on standby.
Both 110V and 220V lines are supported on this unit.