Recently I had to do this and it was a huge learning experience not just for me, but also for the Customer Support Reps at Verizon who some of which have been helping customers for over 5 years. If you are like me, and found the voice quality and reliability of Google Fi's Network to be terrible, and want to move to Verizon here are the steps you will have to go through to make it happen.
First make sure your phone will work on Verizon's Network. In my case I have a Google Pixel 5. I bought it directly from Google, which means is unlocked by default. The phone already supports all the frequencies that verizon requires for their network. If you go into a verizon store its likely they will tell you to just get a new phone, but the problem with that is every phone Verizon sells will be locked to verizon's network. Even after you have paid the phone off they sell phones designed for only their network, meaning if you later decided to move your service to ATT, Tmobile, sprint, ect... the phone will not work since it won't support the other carrier's frequencies. That is one of the bad business practices that verizon continues to go with. If someone from verizon wants to correct that information please reach out.
Verizon maintains a Database of IMEI codes that are phones confirmed to work with Verizon's Network. However this database does not include many phones sold by other carriers. The Google Pixel 5 is one of those phones. So if you take your Pixel 5 to a Verizon store the Rep will search their database using your phone's IMEI code and it will tell them its not compatible. Which is not correct. It does support Verizon's Network, but the rep at the store can not give you an activated SIM card for an IMEI that is on Verizon's database. It takes a Level 2 Tech to do that and then they have to mail it to you. Which is another way to get it working. But there is an even easier way to move to verizon.
You can not add a new user to your existing account. If you login to your account on the My Verizon App and try to add another line of service they will only try to do an IMEI lookup, which will always fail with the Pixel 5. The Join Verizon ( New Account Setup) is the only path that will detect your phone's esim.
If you type in the wrong Transfer Pin or Account ID during the Setup. The only way to get service is to call Verizon and get Level 2 Suppor to Mail you an Activated SIM card tied to your IMEI number. It might take a while on the phone with support, but that is the only solution. Even if you update the Pin with the correct information, the number will port over, but the phone's esim will still not be tied to the account.
Hope this help others who might be trying to move their Google Pixel 5 on Google Fi to Verizon. It does work, just have to go about it the right way.
I finally got my wife's phone (Pixel 5 moved to verizon), Thanks to Rick at the Verizon Store on East O St in Lincoln. It only took him 5 minutes to get it working. However later when talking to L2 Support, they were kind of surprized that it works. They claimed that both our phones ( Google Pixel 5 bought from Google for use on Google Fi ) working on verizon are some kind of software glitch, and that they could stop working at any time. My phone has been on verizon for over a week now, with no issues. They said it could loose connection after a verizon update, or a google update, or even after just a reboot of the phone. I have rebooted our phones many times, and everything still works. Lets hope everything continues to keep working.
Update 10/3/2021
Just to update everyone its been 2 weeks since my last update, and both our Google Pixel 5 phones are still working great on verizon. Though after a drive to marysville, KS to attend a friend's wedding. I found that verizon doesn't quite have the network they claim. We went through several spots where our signal and data coverage was very poor. To the point none of our verizon phones could surf the web, or stream movies and music. Granted I can't expect verizon to setup towers in sparcely populated areas of Kansas to serve single digit customers, but still it would be nice.
Update 4/21/2022
Just another quick update. I can honestly say moving to Verizon has been one of the best decisions I have ever made. Yes I am paying more. But here i am 6 months later. Phone still works great. No dropped calls and 5G and 4G data coverage is excellent everywhere. Even in structures that normally would wreak havok on other networks. I still have my pixel 5, and now I am considering upgrading to a Pixel 6 pro just for the improved camera.