You can't boycott the businesses that aren't doing their part given that most businesses aren't doing their part and the ones that are produce stuff that's more expensive and/or less convenient.

Supply chains are also super complex these days and even the companies themselves don't always report on them properly out of either incompetence or simple denial. That's why every few years we get stories blowing up about tech firms using slave labour to build phones or food corporates ripping off third world farmers.

Working people are tired and worn down and poor and don't have the mental capacity or even the capital to be able to micro evaluate every single purchase decision they make and think "hmm does this company or one of is hundreds of suppliers do their part for the climate?"

For some people it's "I can afford to feed my kids if I use this cheap product from a company that does bad things or I can go without dinner this week if I only buy from ethical companies"

Strong top down regulation is the only practical way to make big companies behave.