Maximum Security for Galaxy Alpha using Cricket

[Voyager39]

I am trying to optimize the security setup for my 2014-5 Galaxy Alpha phone.
I have implemented a 7-digit code for the screen lock function. Additionally, I have installed "Find My Device", and have done a dry run of searching for my phone by logging into Google on my PC, which worked fine.

I am writing to ask whether implementing a SIM card lock is a beneficial or necessary additional step in obtaining optimal security.

Thanks in advance for any input on this matter.