i2cget works, but i2cdetect does not show the device
I have seen this before, with chips closely related to the ADV7610 and even other video chips from Analog Devices.

The chip considers a single I2C read operation as invalid, and it will not acknowledge the address for a read operation because no register address was written to it first.

The chip only responds to a I2C read operation, if it happens after writing a register address before the read.

As far as my memory serves, there must be no I2C stop condition between the end of register address write, and the I2C data read must happen with a repeated start condition.

The datasheet does mention that when invalid register address is used, it will not acknowledge the read operation. But it is not specifically explained anywhere that the sequence does not allow writing register address and reading of data in two separate operations, while it is more common that they are also supported as two separate operations.

Consider it as a special feature of the chip's I2C interface that must be known, documented and handled as required.