OH! TIL! Apparently

                                contiguous              fragmented
    -------------------------------------------------------------------
    PCIe 4.0 NVMe Read Speed    ~5,000 – 7,000 MB/s     ~80 – 250 MB/s
    SATA 3.0 SSD Read Speed     ~500 – 550 MB/s         ~30 – 60 MB/s

Still, given SSDs have a lifespan and given few of my files are that large, I think I'm personally okay without defragmenting. Those numbers are impressive but, most of 10s of thousands of files are source code text files. Asking online what the real-world loss is from not defragmenting

> You are giving up virtually 0% to 3% of real-world performance. In daily development, media editing, and standard system use, defragmenting your SSD will yield no human-noticeable speedup.