Large means VPS, not a braver browser
pdf-lib in a Web Worker is excellent for reorder and unlock. It is a poor Ghostscript. Oversized image PDFs need RAM and CPU on a worker. That is why this page talks about Pro capacity instead of pretending a phone tab will eat a textbook scan.
Trim before you crush
If 40 pages are blank or duplicated, Organize Instant locally and delete them first — no upload. Then compress the remainder. Shrinking pages you will throw away wastes worker time.
Preset for huge scans
Balanced is the default for readability. Maximum if a portal names a cap and you accept softer photos. Light rarely moves the needle on a camera-heavy 80 MB file because the bulk is pixels, not structure.
Privacy on a VPS job
This is an upload. HTTPS in, auto-delete after download. Do not use it as storage. For page ops that never need a server, stay on Instant Organize / Merge / Split.