Jump inside a 'FOR' loop within a BATCH file

Time ago I request some help to develope a short batch file to compress files inside a tree using 7zip, see following link:

Compress separately files within subfolders

Now I want to avoid already zipped files (.7z, .zip files) and jump to the next item.

Also I want to remove previous compressed files (like '.7z.7z' or '.zip.7z') created by using the original batch file several times on a same folder.

This is what I got so far:

@echo off

cd /d %~dp0


rem 7z.exe path

set sevenzip=

if "%sevenzip%"=="" if exist "%ProgramFiles(x86)%\7-zip\7z.exe" set sevenzip=%ProgramFiles(x86)%\7-zip\7z.exe

if "%sevenzip%"=="" if exist "%ProgramFiles%\7-zip\7z.exe" set sevenzip=%ProgramFiles%\7-zip\7z.exe

if "%sevenzip%"=="" echo 7-zip not found&pause&exit


@echo searching...

    for /R %%I in (*) do (
        if not exist %%I.zip if not exist %%I.7zip "%sevenzip%" a -mx -mmt4 "%%I.7z" -r -x!*.bat "%%I" && "%sevenzip%" t "%%I.7z" * -r

)

del "Compressing_files_7zip.bat.7z"

del *.7z.7z*

del *.zip.7z*


::::::::::::::::::::::::::For setting up shutdown 60' after the end of the process.Remove colons in the line below.
::shutdown.exe /s /t 3600

pause

The main issues I get with this code are:

-I am unable to detect already compressed files and therefore, jump to the next %%I entity.

-Remove non-desirable over-zipped files from sub-folders. Obviously, '*' wildcard does not work inside the loop; on the other hand, if I look for 'del %%I.7z.7z' it does not work either.

I read I cannot use a proper 'OR' fuction for the 'if' loops, that is why I nested them.

Thank you in advance.

Alex.