Those are official abbreviations that can be found in a dictionary.
The ones OP posted aren’t all official.
TBH and SMH are official.
IMO is internet slang.
There’s not a lot of consensus on internet slang abbreviations in Danish. It was more common back in the texting days, when all girls would end their messages with an S for “smiling”, SS for “smiling sweetly”, or KKK for “hugs hugs and kisses”.
Those are official abbreviations that can be found in a dictionary.
The ones OP posted aren’t all official. TBH and SMH are official. IMO is internet slang.
There’s not a lot of consensus on internet slang abbreviations in Danish. It was more common back in the texting days, when all girls would end their messages with an S for “smiling”, SS for “smiling sweetly”, or KKK for “hugs hugs and kisses”.
Someone once made an index: https://www.telemarkedet.dk/sms-ordbog-sms-sprogets-forkortelser