I don't find that at all. At work, we've no access to the API, so we have to force feed a dozen (or more) documents, code and instruction prompts through the web interface upload interface. The only failures I've ever had in well over 300 sessions were due to connectivity issues, not interface failures.
Context window blowouts? All the time, but never document upload failures.
I'm talking about Gemini in the app and on the web. As well as AI studio. At work we go through Copilot, but there the agentic mode with Gemini isn't the best either.
Honestly this is as Google product as you can get. Prizes for some, beatings for others.