I don't know if this will help, but I know I had two file manager apps on my Xiaomi / Poco F2 but I "removed" the File Manager app by Xiaomi some time ago and couldn't find it again in the app drawer. It was visible in Settings - Apps but you couldn't launch it from there.
Files (by Google) remained but it won't access system files afaik.
I found the way to bring File Manager (Xiaomi) back (via Reddit) by going to Settings - Apps - Manage Home Screen Shortcuts (for Mi / Xiaomi apps) and tick it there.
I now have the app available in the app drawer. If you open it, the second icon on the top is a folder icon and it takes you to the Android files.
Whether you can find what you need, or you have been this route already, I don't know.
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Added : Yeh... no. Now I've taken the time to look at those folders they're mostly empty.
(note to self : stop posting on short train rides!)