What is wrong with my Mac Pro

If it gets most of the way through the progress bar, the issue is very likely to be the Graphics card.

Try starting up in Safe Mode. Safe mode first does a five-minute automatic disk repair, then loads only a minimal set of Apple-only extensions. The accelerated graphics drivers are NOT loaded. screen refresh will be wonky and slow, but ultimately correct.

Works in Safe Mode but not in regular mode are down to two items: accelerated graphics and third-party extensions.

The initial "chime" sound is generated in software when your Mac passes the Power-On Self Test. If it occurs and/or startup continues, your Mac is working. The blank gray screen should light up. Then on to the disk Drive.

The solid Apple is not in the Mac's ROM at Cold start. The Apple logo can only appear when it is fetched in the first "blob" of software loaded from a 'magic' place on the boot drive, or re-run after a Restart. Then a whole lot of stuff is initialized, and the progress Bar moves part way across. After a cold start, seeing the solid Apple appear says your drive is not completely dead.

The next step requires a lot of files by name, so the File System is initialized, and the Boot Drive is Mounted. If the drive directory is damaged, the drive can not be Mounted, so your Mac begins one pass of Disk Utility Repair. This will take an additional about five minutes. During this process, the progress bar may be extended, and will grow by an additional amount not seen on a routine startup.

at the end of that process (which should not take more than about five minutes), it will attempt to Mount the drive again:

-- if the drive Mounts, boot-up continues.

-- if the drive cannot be Mounted, your Mac can do nothing more, so it powers off.

-- if the process stalls, this may indicate you have Bad Blocks on your Boot drive. The re-reading of Bad blocks can take a very long time (on the order of a quarter minute for each Bad Block).

PUNCHLINE: your drive has clobbered files that can not be easily repaired.

If the image is fairly limited, that may work.

It depends on whether the drive just has a few bad files or a few Bad Blocks that can be repaired by replacement.

Sometimes this symptom occurs because the drive has encountered a cascade of Bad Blocks failures so large, it is overwhelming, and the drive needs to be replaced.

any particular version of MacOS can only be installed by the EXACT same system that will run when completed. so it first copies a bare-bones system to the proposed new boot drive, then sets startup to that drive, then Restarts and starts to move files into place.

If you booted from a correctly made USB stick, and it died while copying that (supposedly incorruptible) software while attempting an install, your Mac has a serious problem

If it tried to copy the files to the proposed new boot drive, then Restarted to begin installation, and died there -- then what you copied is flawed, implicating the proposed boot drive.

does it put up the progress bar? How far along does that get before it restarts?

USB-sticks are not known for their long term stability.

It is possible the USB-stick installer is flawed. It could have developed Bad Blocks.