Yes, you can use SOCKS5 with VPN as they both are compatible with each other and works well. There are few scenario where using these two will provide better outcomes. For instance, you can combine these two when you need to deal with ISP throttling. Also, when you need to stream the online content or torrenting,  you should try using SOCKS5 with a VPN because SOCKS5 let users use to use full UDP and connect to each user in a swarm.