I'm aware of TeamViewer screen sharing, however, the risk is that people might call me a scammer because it allows me to control the computer which I'm connected to, even though I have no malicious intentions. So what app should I use instead?
If you think that the one you are helping can do the steps you are telling him (which usually is not really true or it's extremely slow), Microsoft Teams, Skype or Zoom allows you work with screen sharing in view only mode. Possibly also Google Meet, but that one I never used. Some of these options also allow you get full control of the other's computer if (and only if) the other user allows it.