That is probably exactly a case where you don’t want a qlc drive. As long as you stay under the cache it may be quite fast and the good mbps/w looks good, problem is the drive has to stay on after that to shovel all that stuff slowly to the non cache part whereas the tlc drive would be done at that point. So total power used for your workload is probably not actually better and likely a lot worse but workloads like that are quite hard to benchmark.
For a workload that does little writing and a lot of reading however qlc is mostly fine and the price does tend to make most of the shortcomings at least somewhat worth it.