After spending several hours I have installed the front assembly on the Corsair Obsidian 750D Airflow Edition which evidently was damaged in shipping. Now the front air filter stays put better but the design might be better using a magnetic assembly.
The front panel assembly is screwed onto the front bezel which had to be detached to remove the damaged part. Once it was freed (4 screws) the panel was easy to remove. Reversing the process showed how the top face clips into place to secure the main bezel.
The front air filter now pops in properly so the replacement bezel has been successful in restoring the machine to intended design.
The replacement fan is not broken so it was left to pull cool air into the machine. The replacement fans can be kept as spares should a fan fail. Corsair sent 2 fans when I indicated only one had failed. Testing the dead fan on another machine showed it to be completely DOA. The 750D uses a pair of front fans along with a rear fan, The Corsair H115i water cooler adds two more fans.
Updating the iCue 3.x to iCue 4.x software seems to work with the components I own better. iCue 3.x could not set a custom fan for the HX1000i but version 4.x can. The temperature fell almost 15°C following the custom fan activation. Cooler operation should improve service life. iCue 4.x also supports temperature color for the H115i which is the same as the motherboard RGB capability. The K55 keyboard now is a static white which makes it easier to use when touch typing.
USB 4.0 is now standardized so the next generation motherboards will likely be supporting more USB-C ports along with USB 4.0 performance. The migration from USB-A to USB-C will be hybrid as there is vast installed based on existing USB devices.
To support the USB front boxes a PCIe USB 3.0 card with dual internal 19-pin headers is installed. A front USB box with a pair of USB-C ports and a pair of USB-A ports is ideal for transition purposes. USB cards are available with all combinations needed. USB changes probably will take 5-10 years or more. USB-C to USB-A boxes are widely available already.