If you've got a 10gbps server that's attracting 100gbps of UDP reflection DDoS traffic, and your host has ingress capacity for that, their easy/simple/low cost options to help are most likely null-routing your ip, which doesn't really feel like helping, or dropping udp to your ip.
If you're running a UDP service, you're going to need something more complex. maybe the host can drop all udp but port 80, but maybe the DDoSers can generate the reflection traffic to port 80 instead of random ports. If you're getting too much volumetric DDoS on your service port, you'll need to have some sort of filtering that understands your service traffic better and has enough ingress capacity. Usually that's expensive, not super flexible, and often adds a lot of latency.
If you're running a UDP service, you're going to need something more complex. maybe the host can drop all udp but port 80, but maybe the DDoSers can generate the reflection traffic to port 80 instead of random ports. If you're getting too much volumetric DDoS on your service port, you'll need to have some sort of filtering that understands your service traffic better and has enough ingress capacity. Usually that's expensive, not super flexible, and often adds a lot of latency.