No one gives you any guarantees as in the weaker exchange. But, mixers are a business depending on whether people will use their services or not.
Obviously, stealing coins from someone else will pop up and leave a shadow on the mixer’s reputation. Therefore, you should choose only trusted and time-tested mixers.

Here are a few of them:
Mixer.money
Bitcloak
Bitblender
Chipmixer

All of them are on the open Internet, but there are also mixers that you can enter only from the Tor network.

Or, as advised above, you can use the CoinJoin method. Its meaning is to unite several transactions in one pool. Note that if you use this method, the digital footprint may not be completely deleted.

The above mixers are not a recommendation! In any case, you need to conduct your own analysis and make a choice.
Pay attention to the reputation of each individual mixer, do not neglect to read reviews.