What’s a funny word for someone who is frequently breaking things?

There's many.

The person is Clumsy or a Klutz or bumbling.

See here for more synonyms.

Consider using something simple like accident-prone, absent-minded, or careless. Maybe they’re just forgetful, but there’s also inattentive, preoccupied, or scatterbrained. For meetings and such, they could be said to be unreliable or undependable.

Those aren’t as strong as an elephant/bull in a china shop or a walking disaster, or even an accident waiting to happen.

If it approaches the criminality of wanton disregard, it might even be negligent.

From Yiddish we get a whole host of “oopsy” words, like klutz and klutzy, or a schlep, a shlemiel, or a shlemazel. Those all have different connotations.

Some of those don’t sound too mean, but others do. For someone who always has their head in the clouds, you might also go for airhead or space cadet, or perhaps bumbler.