I’ve had O’Neil replace our water heater, which is what you’re likely looking at if it’s leaking without any specific disturbance done lately to it. They’re metal with a thin glass coating and a sacrificial anode/rod. There are expected defects in the coating and, once the anode gets sufficiently consumed, it’s the metal body that starts corroding and you get a leak.
If it can’t be repaired, consider a tankless unit, unlimited hot water. They are fantastic. Mine has been installed for over 10 years – no issues. Love it!