Will your chatGPT4 think of itself as GPT-3.5?

I’ve encountered some issues with ChatGPT recently. Specifically, even when I select the ChatGPT4 model, it seems unable to perform functions exclusive to GPT-4, such as calling DALL·E, conducting web searches, or accessing uploaded files like PDFs or Excel documents.
When I upload a PDF, ChatGPT simply ignores the file and asks me for it again. Despite selecting ChatGPT4 manually or choosing GPT-4 in dynamic mode, it still identifies itself as GPT-3.5.
I’ve tried inputting in multiple languages (Simplified Chinese, Traditional Chinese, English), but the issue persists. I’ve also attempted using different devices, browsers, and proxies to rule out device-related issues, but the problem remains unresolved.
I tried searching for similar issues in the forum but couldn’t find any viable solutions. Have others encountered the same problem as me? Has anyone found a solution?