"I wonder if a DLM reset might get my speeds back to where they were?"
You'll have to post your connection stats to get that question answered.
Your stats would suggest DLM hasn't taken any action on your line. If you are connected to a Huawei cab then G.INP may kick in within 14 days and increase your speed. This is totally automatic and cannot be actioned remotely.
Well, nearly 3 months on after the initiall problem my intenet speeds are finally back to normal. The fault was fixed a few months back but after the fix my download speed was stuck at 60Mbps compared to my usual 65. I just decided that was that and would have to accept those speeds were the norm from now on. But today I'm back up to 70Mbps which is close to the speeds I was getting when I first got infinity.