Many of the older PMDG liveries can no longer be used by anyone who has not updated their aircraft to the 2024 variants to have access to OC3. OC2 is no longer functional. I suggest splitting the liveries in three groups.
OC2 compatible (basically 2020)
OC3 compatible (basically 2024)
Native (not in any proprietary format from PMDG but in the standard MSFS format)