I think non-Gregorian date arithmentic should throw in roughly the same situations as Gregorian date arithmetic.

A case that differs is in calendars with leap months (chinese, dangi, hebrew). Currently the spec says:

If calendarDate.[[MonthCode]] is a leap month that doesn't exist in the year, then:
i. If overflow is reject, throw a RangeError exception.

But, this is stricter than in Gregorian, which happily allows an ephemeral date to exist so long as it is then moved into a regular month:

// Error:
Temporal.PlainDate.from("2024-02-29").add({ years: 1 }, { overflow: "reject" })

// OK:
Temporal.PlainDate.from("2024-02-29").add({ years: 1, months: 1 }, { overflow: "reject" })

// Error:
Temporal.PlainDate.from("2024-02-29").add({ years: 1, days: 1 }, { overflow: "reject" })

I don't see why LeapYear-M05L-01 + { years: 1, months: 1 } should throw if it doesn't do that in Gregorian.

To fix this, simply remove that one RangeError. The one a few steps later will still trigger if the days are invalid.