Freezing for the big three went smoothly. I started with Equifax: firefox with duckduckgo plugin didn't play well. So I moved to Edge with no add ons.
Once there:
Equifax - simple
Experian - simple
Transunion - accidentally got on their paid page. Started over. A few pages were not loading, but a stop and refresh brought them up. Done in 5 minutes.
One of the providers mentioned that they use some info from your wireless carrier to help identify you. What this means to me is you really, really need to have a sim lock with your carrier.
Secondly, you better also guard your email address carefully. That is becoming way too key.
Overall, it was disturbing how easily they "verified my identity". Very few questions, mostly just asking for the mobile phone number.
The last time I tried this was about 10 years ago. Back then, I had to answer about 5 mysterious questions about things like previous addresses or mortgage companies, and so on. I got none of that. Those questions (which frequently were "none of the above") was one reason I was hesitant.
Also, I had an account with Equifax I made 10 years ago. It was invalid. They changed too much.
Just having an account with these three is important. Do it before someone else opens an account for you. I'm sorry to say I dragged my feet so long, but that's water over the dam. And make sure you have an account with Social Security and the IRS before you freeze. SS uses Equifax to verify you. I don't know what the IRS does, but it may. Or you can always unfreeze, but in any case, you need accounts with both of those so they don't open one up for you.
Now I have to ponder whether to look into the lesser bureaus. Here's the list. LexisNexis is first on my list. This BH article has links to the freeze page for them too:
Credit freeze - Bogleheads