Trouble with RootFS package management on proot (Termux)
For proot on Termux (no root, based on a trimmed Linux kernel), it's rather difficult to manage packages in RootFS. Neither chroot (due to no root) nor fusermount (seems no kernel support on Android, or root required) would work. 

Lately I tried wine on FEX and installed wine 7.0 on host OS. But FEX seems to prefer RootFS files (wine-5.0 and libwine.so) over host OS files but I couldn't manage RootFS packages. Can I change its preference for host OS vs. RootFS? Or how could I manage (e.g. `apt`) or remove RootFS packages given chroot and fusermount not available?

I would be grateful  if you may provide more details on FEX mechanism, which I couldn't find from Wiki page. Why does FEX need RootFS when Ubuntu/Debian MultiAarch is there (won't it be good to, or can I, run FEX with only MultiArch and without RootFS, just like box86/box64)? What makes RootFS different from FS from a typical distro image or chroot FS (does RootFS replaces any Ubuntu files/libs with thunklibs)?

Thanks a lot!