Local Admin through Group Policy Update (Concerns)

Question

Hello Everyone,

I managed to successfully add local admin through group policy in the domain PCs by following the instruction from the video below:

https://youtu.be/ps3peoLU1BI?t=293

I still have few concerns relating to this and would really appreciate the help from everyone:

1. At any point do we have to resync and update GP to keep this group/user as local admin
2. Is there a chance of password getting expire
3. Is this safe
4. Is there a better way to do it

Any help will be appreciated.

Thanks in advance