If you don't need range scans, have you looked at WiscKey approaches? https://www.usenix.org/system/files/conference/fast16/fast16...

There are a number of implementations including Badger (used in dgraph) and a variant that's "RocksDB for large-value use cases" (https://rocksdb.org/blog/2021/05/26/integrated-blob-db.html)