There are actually more than 3 providers and you should put a freeze on everything you can. You only need unfrozen credit for applying for new lines of credit (loans, credit cards, etc), and unfreezing is a quick process (15 minutes or so).
Here’s a pretty comprehensive guide for protecting yourself: https://old.reddit.com/r/IdentityTheft/comments/uvv3ij/psa_freezing_your_three_main_credit_reports_is/
It’s better to take these steps before you get your identity stolen rather than after. These steps can prevent your leaked information from being used against you.
Even if some of the information is outdated, although I believe it’s all still valid, the main points / TL;DR are absolutely relevant. It’s unlikely that the main bureaus will change, and although the exact steps for freezing may change over time, the emphasis on freezing is important.
