Why is Primavera only certified on Oracle Database version 19.3 and 19.8?

We are on an exadata machine and currently we are upgrading all our database system off 11.2.0.4 onto a certified 19c platforms which was 19.4. I left Primavera last as I thought it would be easy to do but have found the upgrade from 11g to 19c doesn't work. I have logged tickets only to find out that Primavera is supported on only 19.3 and 19.8.

I doesn't make sense to me that you only support the product on specific database versions. Being on an Exadata our next patching cycle (which we have to do every 12 months) will takes us to 19.10 or 19.11.

On exadata it is difficult to have to maintain too many oracle homes so we strive to be on at least n-1 .