You're right, the market is flooded with simple "button grid" apps. That saturation is actually why I built FlowPDF.
I didn't want another list of basic tools; I wanted to chain them. I built a node-based editor so you can create actual pipelines (Merge -> OCR -> Filter -> Compress) rather than just doing one-off tasks.
I think that's the only way to actually add value over the 50 other "Hello World" clones.
https://www.flowpdf.app/ if you wanna check it out!
I've been working on exactly this with FlowPDF (https://www.flowpdf.app/). It was a huge pain to find a tool that didn't rely on Google APIs.
I integrated a local translation model. It downloads the model to your browser cache on the first run (so it's a bit heavy initially), but after that, you can OCR and translate documents 100% offline without uploading anything.
I actually built a tool called FlowPDF - https://www.flowpdf.app/ - specifically to solve this "logic" problem. I found that single-button tools were too limiting for things like "Merge -> Check Size -> Compress".
It uses a node-based graph so you can literally string those steps together (e.g., Merge files -> Split out page 35 -> Compress the rest) and save it as a repeatable workflow.