I wouldn't expect using a log-structured filesystem to help much, because the SSD is already running its own log-structured filesystem internally.
A log-structured filesystem doesn't magically turn a random write workload into sequential writes; it incurs more or less the same overhead that the SSD's FTL does doing read-modify-write cycles causing write amplification.
A log-structured filesystem doesn't magically turn a random write workload into sequential writes; it incurs more or less the same overhead that the SSD's FTL does doing read-modify-write cycles causing write amplification.