FTP alternative for production

I'm currently managing two physical servers, both running Red Hat Linux 8. The primary server is configured with the OS on bare metal, whereas the secondary server utilizes Hyper-V for virtualization. Both servers are dedicated to a single service, FTP, which has recently been experiencing issues. Given that these servers are in a live production environment, I am exploring alternatives to FTP that could offer improved reliability and performance. Could you please suggest any viable replacements for FTP, considering the current setup of my servers? Your advice would be greatly appreciated. Thank you.