>defragmentation won’t achieve much

Indeed, most Linux setups supporting trim, already defer these operations to a weekly schedule to reduce wear, and most fs will optimize in 10MB or 25MB chunks given unlike HDD... the SSD seeks are nearly constant time. Logging fs like f2fs, are content aware so will auto re-locate hot and cold (rarely modified) file types, and despite the log-structure... on an SSD performance losses are often surprisingly negligible.

Most modern NVMe with dram cache and SLC buffer areas also defer committing pages to low-endurance flash areas. And most kernel tweakers will set swapiness to 1 on SSD/NVMe machines to try to keep stuff buffered in dram as long as reasonably possible. It is a space-time tradeoff that can boost a desktop machine performance especially with preload daemon active.

If people want ludicrous speed... than just run ext4 with a separate 128GB journal NVMe drive on a split PCIe x4 bus.

Defrag on most modern drives usually just fills these buffer areas full, and things grind to the slowest i/o choke point. =3