@knowledgesharing. ASME IX 2019 not listed material grade S275JR in table QW-422. We also faced many the same issue for alternative material, designed drawing is ASTM A36, but purchased material S275JR because available in the stock or short order.
Your question the same issue in the topic WPS for S355J2 and Welding produre qualification for structural steel .
Except BS EN ISO 15614-1 grouped material based on the minimum specified yield strength such material A106-B or A36, S275JR, … grouping in the grouping 1.1. So, you may make a procedure sub-group 1.2 also qualify for group 1.1.
In this situation, we would like to recommend 2 options.
Option 1: you make a Technical Query and submit to your client and get approval as equivalent.
Option 2: If not accept by them, you have to made a new PQR for unlisted material (S275) to listed material.
For secondary structural steel or supporting material, your client may consider to approve your suggestion in Technical Query (option 1).