VPC to VPC connectivity

A customer has an on-premise data platform (Hadoop) which gets data from third party Oracle DB Read Replica (hosted on EC2 instance of AWS system owned by said 3rd party). Migration of this data platform to AWS has been considered. There is a question on method of connection between this migrated data platform (on AWS) and the 3rd party read replica (in a separate AWS env). One of the suggestions is VPC sharing, which for security reason, is not allowed. What other options can they consider for connecting their VPC to this separate VPC that's owned by the 3rd party? Site-to-Site VPN, TGW are some of the suggestions but would love to hear some recommendations.