Venmo is not a money laundering tool unless you're dealing with laundering super low $$,$$$ per month.

Everything has to be linked to a bank account, which is completely verified and has all your info, they have checks on the amount that you can send per day, per person, and per timeframe (say a week or month) and don't support multiple accounts on the same device (so you'd have to log in and out of multiple accounts on the same device, which is time intensive and likely to trigger a flag in their system saying the device used 7 different Venmo accounts to send/receive money).

The banks also have their safeguards in place, so you can't just deposit $,$$$ from several Venmo accounts to the same bank account.

And you can't send the crypto you purchase on Venmo (through your Venmo wallet/deposit from bank account) to anyone.

Keep in mind, Venmo is US-based and owned by PayPal (US-based), which is a publicly traded company and subject to all the audits/lawsuits/protections there are