OK. I've had this happen on two different iPhone 15 Pros. On each, I used Quick Start, and I let it activate the line (not transfer, just activate - I purchased the phones linked to Verizon numbers, not "activate later"). I had activation problems with both.
IMPORTANT - on the Verizon web site for my account, on the device page - the device showed as tied to IMEI2, BUT the number they listed next to it was actually the IMEI for the phone. That's going to cause problems if your eSIM thinks it's using one number and Verizon thinks you're using the other.
The default activation process seems, in some instances to be mis-linking the IMEIs with the account. If that's true, you need to communicate to Verizon the actual IMEI and IMEI2 values, and ask them to compare them to the account setup. They will need you to be connected to Wifi, they'll attempt to reactivate the phone, and you'll have to reboot. Possibly more than once.
In each case, when it came back up, the phone was activated, I could place and receive calls, but I now had two "active" eSIMs - the one Verizon activated, and the "bad" one from the initial phone setup. I also had two signal strength indicators.
They appeared on my phone (YMMV) as "Primary" - the one that didn't work, and "Cellular Data" - the one that did. When you go to Settings -> General -> About, you'll see that one of the eSIMs shows "Unavailable" for the Network - this is the eSIM that needs to be deleted.
Just go back over to Settings -> Cellular and delete the eSIM that lines up with the "Unavailable" network, and your eSIM list will collapse down to 1, you'll get 1 signal strength indicator back again, and on Settings -> General -> About you'll see your eSIM tied to IMEI2, which is what Verizon expects by default, and IMEI will show up as "Available SIM".
Sorry for the wall of text. I just had a very consistent experience with this, thought I'd share. Also, the agent you get is critical - the first time I went through this, the rep understood EXACTLY what I was telling her, knew exactly what was needed, it was probably the perfect tech support call, I was never asked to do something I had already done! The second one, the agent wasn't so experienced, and I had to walk them through it a little more. Escalate if you need to!