How to find a result without hyphen

Setup

• Solr version:
• Drupal Core version:10.4.3
• Search API version:8.x-1.38
• Search API Solr version:4.3.8
• Configured Solr Connector:solr9

Issue

The product SKU is RM-5. The SKU is indexed as ngramstring. I was able to find the product by searching "RK-5". However I cannot find the part by search "RK5". How can I be able to find the product with "RK5"?

Thank you!!