Was just on an overbooked Delta reward flight. They needed 16 volunteers to leave the plane in order to take off, which delayed us nearly an hour after we had already boarded. Then they said they had to dump fuel to lose more weight. Then bad weather delayed us another couple hours, at which point the crew timed out, so we deplaned, waited another couple hours, and the flight was finally cancelled.
While waiting I booked another, much more expensive reward flight for tomorrow (ironically the same flight they had originally offered me $1500 to switch to

), which turned out to be the right move as that flight sold out immediately and they were not able to put me on anything for the next 2 days. When I called, they refunded my original rewards flight and offered me 10k miles compensation, which doesn't come close to the difference in the 2 flights, let alone the fact that I am out 2 ubers, a hotel night, and other expenses. I declined this offer as she told me once an offer is accepted I likely wont get a better one. She also mentioned that she sees it was an "involuntary cancellation", but that on her end it shows it was due to weather.
Was I correct in declining the 10k? The online reimbursement form for Delta seems extremely limited, there is nowhere to add any context. Is that the best way to request compensation? What's my best option at this stage?