Safest way for rooting I would not recommend rooting a device that is still under warranty.

I am trying to find a way to root my old device from 2014 that has become my daily because the new one got damaged and cannot afford a new one. It runs on Android Lollipop.

I am trying to avoid the traditional root way which involves unlocking the bootloader and then flashing it with different files. I am not comfortable in doing that since it is risky and my brick my phone from a mistake. There are tutorials on doing it for my exact phone model so that is not the requirement here at all.

I also know about the one click root solutions but there seems to be a lot of debate on its safety as it is not clear what info is being collected by the app developer. I did kingroot on my test device and it is fine for that device but I don't want it on my daily.

I have found a way which "on paper" seems the safest. It roots without rooting the device. However, I would still like to make sure that it is safe before I use it.

In the below link there is a video that is about an app called VMOS which allows to duplicate the O/S (done automatically) and creates a virtual O/S on top of the locked one on the device and then the virtual one can be rooted.

https://www.youtube.com/watch?v=UUTxMGsM_Uc

The app has been removed from the "Android Play Store". I am adding below the FAQ from their website. In the FAQ they mention that they do not collect any data and that the only data they collect is for error logs. 

https://www.vmos.com/faq.htm

Can that claim be trusted? Would anyone trust that they are honest and do not collect any other data.

I don't think that the app can be put behind a firewall because then it might block all the apps that are running on it as it is the main gateway for them.

I am also sure that running a virtual O/S would require to use more resources on the device. So this solution would not be useful for just any device.
As far as the app you found my impression is, that it is as of until someone of standing in the community can legitimately say otherwise, that its ability and origin are &quot;questionable&quot; at this time. I have only seen a few people even comment ABOUT it, let alone bonafide users that actually USED it and have some form of empirical data that can back up any claim to it being effective/non-spyware related/not full of issues like bricking peoples Galaxies, Lg ThinQ's (god I love mine), Note, etc., and so on. If it is a usable way of being able to solve some issues for the general public than I'm all for it but hopefully someone can start showing some good hard data on this for everyone.