As with the passage of time more people are entering the cryptoworld and we can see there are many scammers nowadays so can you suggest any ways where newbies could earn btc without investment.
Giveaways, games and rounds, campaigns, bounties (selling tokens/altcoins into bitcoin).
Those are the possible ways that I can think of.
Literally speaking, if we are talking about investment in terms of money, those ways that you've just mentioned are the best way to earned some dust of bitcoin, you need to be positive in order to find comfortable ways to earned, tough task from the beginning but along the road you will learned more and
for sure you'll going use doing it.
OP is looking for a way that he don't have to put any amount to have bitcoin.
through airdrops, can't believe on that story, he/she is just making up a story or its a fact.