UA markets these as premium routes with lie-flat seats. That is part of the extra fare you are paying beyond the lowest available Y fare which is arguably the ‘cost of transportation from A to B’.
Booking this route 30+ days out showed a $414 premium for J over Y. Booking this flight on day of departure showed a minimum of $1,250 premium, and as high as almost $3,000.
OP paid a premium for a lie flat seat and did not receive it in any form. The conversation should not be about compensation but about how much of a refund is due, of which the difference between the fare paid and the lowest available Y fare at time of booking is the start of that calculation. Compensation should be a customer service gesture beyond the refund amount to cover the inconvenience.