Icloud emails vanished (after multiple other issues in 2 weeks)

thank you in advance. I feel like I'm in the twilight zone. Yesterday, all my icloud emails were on my phone and macpro. Today, they are gone - ON my phone I have one from this morning, one from yesterday and one from Monday and then the most recent is from 9/17/2023. Including emails I received yestserday, or pulled up yesterday. My mac has about 8 for the past 10 days then back to 2023. Checked on Icloud and I have one or two a month for the past year...sadly mostly things I sent myself from a separate gmail account. I'm at a loss how do emails just disappear? I'm desperate to find many emails....and even more desperate to find excel and word files that have disspeared (from my computer, and all clouds including microsoft) or cannot be accessed Excel files that are even listed say "this file cannot be accessed the file is either deleted or not currently accessible" word documents that can be found- "cannot be opened user does not have access privelages". more background 10 days ago I turned on my computer - having expected it to update to sonoma overnight, it had not updated but it no longer recognized me as a user, I had to reset the password just to get into the macbook pro, and reestablish accounts, passwords on evetying (gmail accounts, NY times accounts - anything ) I spent hours on a chat with apple...couldn't do much but they set up a call for the next day with a higher level support person, hour with them, got some things back, had me update to sonoma (succesfully) and then a new support person called me back - empathetic but said looks like i "lost a lot of data" - why how? set up a quick user account as directed and had me try to access the missing files to no avail (can't imagine why they would come up from a new user anyway) THEN TODAY--- icloud messages evaporate.. ....any suggestions would be immensely appreciated. I can't lose this stuff, much is irreplaceable --- isn't that why I'm paying every month for cloud storage???