We are facing the same problem with eclipse-temurin:17.0.12_7-jdk and application has been deployed in AKS and using the below GC parameters for one the application, still seeing G1 Old Gen utilization is more than 70%.

-XX:MetaspaceSize=128m -XX:MaxMetaspaceSize=512m -Xms256m -Xmx4096m -Xms512m -XX:+UseStringDeduplication -XX:+UseG1GC -XX:MaxGCPauseMillis=200 -XX:ParallelGCThreads=20 -XX:ConcGCThreads=5 -XX:InitiatingHeapOccupancyPercent=45