There’s nothing wrong with the update system that would cause what you describe - it works extremely reliably (on hundreds of thousands of devices) and a lot of care and attention has gone into its design and testing.
Almost certainly you have a hardware issue such as one of the following:
- Faulty SD card
- Inadequate power supply
- Too much overclock (try reducing your overclock to default)
(This is not an exhaustive list)
There is a small chance that some additional 3rd party software you’ve installed may cause an issue during upgrades but it’s uncommon.
Anything that causes a crash or file system corruption when writing to disk is going to cause you problems when you upgrade because you are overwriting lots of critical system files during the upgrade process - so any subtle hardware issues you have that might not cause apparent problems during normal operation will tend to show themselves at upgrade time because so many boot critical files are written to disk during an upgrade.
If you see any text being displayed over the OSMC splash image during boot it means an error has occurred during boot, typically a service failing to load - if you could get a photo of this error it would be helpful, although I suspect that the root cause of your problems is going to be disk corruption.