You only need to wear one condom at a time. Wearing two doesn’t add extra protection, just extra hassle.
That said, it’s a good idea to have more than one condom on hand so that if one breaks or comes off during sex, you have another one to put on.
If you want to add a layer of protection to condoms, here are some ways to do that:
If you’re the one wearing the condom, pull out before ejaculating.
Use PrEP to prevent HIV.
Get tested for STDs regularly.