How to recover photos that are missing from camera roll on my iPhone?

Today I was looking for photos to print and I noticed gaps between my days then months then weeks. I take a photo almost every day. Prior to this day I had near 15,000 photos from what I can remember. My Phone is now saying I only have 5,978. I never delete my photos! I pay for the .99 Icloud+ for my to get 50GB of storage to ENSURE my photos stay. I looked up online to see what I could do and it told me to check the following: I have checked recently deleted nothing. I have checked hidden photos nothing. I have went to settings and clicked Icloud then photos nothing! This is so upsetting my photos mean everything to me. Everything before March 2023 is gone. On top of that I do not even have everything after that. Random gaps of missing photos from March 2023 to now are missing. Online is telling me to check my cloud. How do I go about doing this. Please assist!

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