Yes both devices are on the same account.
The tablet has its own SIM and phone number.
I would prefer not to use the Verizon messaging app.
My Note 10+ is unlocked and I use Samsung messages.
If it has it's own cell number you will not be able to sync messages and calls. At least not the way you are wanting to. That would be like a couple having the same plan, each call he gets she gets, each message he gets she gets, so on and so on...
I do have a solution however. Google Voice. The reason Google Voice is one of the most attractive options is because you only need to register one device, I would opt for the phone if it is your primary device, and you have access to the call log and messages, mostly.
OK Google here I go, if you're reading this I want my commission; LOL
With Google Voice when you register it will give you a Google phone number. I like the Google phone# because I can give it out and not my personal number, and it is supper easy to block callers. Here's a short list of other things Voice can do;
Customized/personalized voicemail greetings. Tell Grandma you love her every time you send her to voicemail, I mean miss her call.
Free Visual Voicemail. Turn voicemail messages into text and have them delivered as SMS messages to all of your devices. Read, listen to or access GV VM from any device you can log-in to Google.
Link up to 5 devices to your account. When you get a call on your G# or carrier number the call will ring all of your devices like call forwarding so you will never miss a call. Even forward calls to landlines. If you receive a text it will be sent to all SMS capable devices.
Send or receive calls and texts from your Google # just like you would your carrier number. Plus the piece of mind that you are not using your personal number and callers can be easily blocked.
With the Google # send select callers directly to VM and never have your phone ring but always get the message.
Send callers to directly to VM, never have your phone ring, have a personalized greeting play but do not allow them to leave a message. Yeah read that again... That's right. *If you are using your carrier number the phone will ring but the rest will still work.
There are probably a handful of other things I'm forgetting, but long story short, this is one way to get what you're looking for. I believe they updated the service so you can make Voice your primary and it allows you to do even more using your personal number.
Oh and I forgot to mention that it is free. "Google" free, so yeah they are going to collect every piece of data they can on you and your use of their service, just like they do when you search with them, go online with them, pick up that Android branded device of theirs, etc. etc. etc.