I have an ugly little workflow that I knocked together in Python (mainly using Pandas), with Dropbox to move the result around, and Google Sheets to view it. It runs nightly from my local machine and pulls out all my parts list into a single CSV (with a column indicating which Rebrickable part list the part is from). It creates a date-stamped version of the CSV (for backup) and a "always the latest" version. The latter is synced to Dropbox and I have a Google Sheet that reads it live (using the IMPORTDATA function).
This workflow gives me a backup of my parts lists and and a quick way to search for parts in Google Sheets if I don't want to go through the Rebrickable interface. I find that I use both Rebrickable and the Google Sheet depending on what I'm doing. Also, as an intended benefit, I can go back through the date-stamped versions to see how my parts total has changed over time, which is probably about the nerdiest thing I've ever done for fun.
If that sounds like it might be helpful to you, send me a DM, and I can send you the script. You'd need to be comfortable in python to make any sense of it, but it sounds like you probably are.