How to exclude "DEBUG" without throws "BUG" in grep

I trying to build a command to grep common list of error keywords(e.g. bug occured!, error, exception), but need to exclude common keywords too (e.g. DEBUG tag) without throws the matched line. This command should robust enough to handle miscellaneous of source/log.

Let’s say I have this source:

$ cat dummy.log 
12345   DEBUG   debug.log abc
!DEBUG
!bug
!debug
DEBUG noop
12345 DEBUG bug occured
please report BUG to me
the filename is critical_bug.log
bug should be fix.
noop
throws error
a stuff
b otherstuff
c otherstuff stuff

This command will not work because it excluded the bug lines(i.e. 12345 DEBUG bug occured) which contains DEBUG:

$ cat -v dummy.log | nl | grep -Ei 'bug|stuff|error' | grep -Evi 'DEBUG|otherstuff'
 3  !bug
 7  please report BUG to me
 8  the filename is critical_bug.log
 9  bug should be fix.
11  throws error
12  a stuff

Change the order of pipe also same as above:

$ cat -v dummy.log | nl | grep -Evi 'DEBUG|otherstuff' | grep -Ei 'bug|stuff|error'
 3  !bug
 7  please report BUG to me
 8  the filename is critical_bug.log
 9  bug should be fix.
11  throws error
12  a stuff

Try to use ^ in grep ([UPDATE] wrong, ^ is not for exclude), but it included the DEBUG noop which doesn’t contains bug (note: all of the filter should case insensitive, e.g. I want to accept BUG occured! and exclude debug.log):

 $ cat -v dummy.log | nl | grep -Ei 'bug|stuff|error|^DEBUG|^otherstuff'
 1  12345   DEBUG   debug.log abc
 2  !DEBUG
 3  !bug
 4  !debug
 5  DEBUG noop
 6  12345 DEBUG bug occured
 7  please report BUG to me
 8  the filename is critical_bug.log
 9  bug should be fix.
11  throws error
12  a stuff
13  b otherstuff
14  c otherstuff stuff

I can’t customized to exclude only debug if I only use -w (e.g. the filename is critical_bug.log failed to include):

$ grep -wnEi 'bug|stuff|error' dummy.log 
3:!bug
6:12345 DEBUG bug occured
7:please report BUG to me
9:bug should be fix.
11:throws error
12:a stuff
14:c otherstuff stuff

My expected output (Note: I need to keep matched color and original line number):

$ grep -wnEi 'bug|stuff|error' dummy.log 
3:!bug
6:12345 DEBUG bug occured
7:please report BUG to me
8:the filename is critical_bug.log
9:bug should be fix.
11:throws error
12:a stuff
14:c otherstuff stuff

Is it possible make this in grep or alternative command?

$ grep -niP '(?<!de)bug|(?<!other)stuff|error' dummy.log 
3:!bug
6:12345 DEBUG bug occured
7:please report BUG to me
8:the filename is critical_bug.log
9:bug should be fix.
11:throws error
12:a stuff
14:c otherstuff stuff

-n, --line-number
    Prefix each line of output with the 1-based line number within 
        its input file.

-i, --ignore-case
    Ignore case distinctions in patterns and input data, so that
    characters that differ only in case match each other.

-P, --perl-regexp
    Interpret  PATTERNS  as  Perl-compatible regular expressions (PCREs).
    This option is experimental when combined with the  -z  (--null-data)
    option, and grep -P may warn of unimplemented features.