my comment (not an STM answer):
Why not? It should be the same die (same chip inside the different packages). The datasheet is for STM32H753xI and all the related parts are mentioned as packages available. e.g. as: STM32H753BI and STM32H753VI (the T6 is just the package and temperature range). See in datasheet on page 2 as "All packages are ECOPACK2 compliant".
I would heavily assume: all packages have the same die inside.
Background info (about die and packages):
Very often, the same die (real silicon chip, inside package) is the same just in different packages.
A smaller package will just bond (wire) a subset of the potential pins, a larger package will bring out more signals (pins). Bonding (wires) from the die to the package pins.
Such a package can have a "bumper" inside: a hidden pin which is "soldered" (tied to GND or VDD) which controls which features are enabled. So, in a smaller package, possible that the same die is used, but this "bumper" disables some features (e.g. memory size, devices available).
Conclusion:
I would assume, the same chip number, e.g. STM32H753 (as STM32H753xx or STM32H753xl in datasheet or even in STM32 HAL driver code) is really the same die (just in a different package).
Chip vendors use a different part number when their internals are different. They keep the same chip number when the same die is inside, they just augment it by an auxiliary package information.
Chips never vary via packages, just via part numbers.
