I have taken advice from @ryerman and started a new thread so that I can get an answer by providing a more detailed explanation of what I need to achieve using mp3tag in the hope that you can better assist me.
I have a list of artists that I want mp3tag to find in fields such as ARTIST, ALBUMARTIST, TITLE (and preferably FILENAME):
abba|adda|absrdst|acdc|ac dc|akdong musician|bkpr|blk jks|bts|chllngr|chvrches|chll pll|dfrnt|diiv|dmc|dnce|drwn|dtcv|dwntwn|dvsn|dvsr|exo-k|grmln|haim|htrk|hxlt|inxs|jmsn|jpnsgrls|kaytranada|kda|kshmr|ladybaby|lany|lee hi|lndn drgs|lnzndrf|lvthn|mgmt|mika|mnek|mndrmnek|ms mr|mstrkrft|n sync|nsync|partynextdoor|pwr bttm|pza|rdgldgrn|rkcb|rlyr|rÜfÜs du sol|rvivr|ry x|sbtrkt|shxcxchcxsh|sophie|stnnng|strfkr|swmrs|tnght|tr/st|tts|tstr|walk the moon|wzrd|u2|u-kiss|unkle|wstrn|xtrmst|zayn
When it finds an exact match in any/all fields, it should force UPPERCASE for all instances found in each field. It should be a strict search that looks for exact matches of the above (like 'n sync'). It should not force uppercase if it finds 'n' or 'sync' on their own (for example).
It should require only one action (not one action group) and one list, preferably incorporated within the action, but located in a text file if necessary.
We have experimented with guess values in the previous thread without success due to my limited knowledge, experience or understanding (although I am trying my best) of the regexp language.
I look forward to hearing from you