The funny part here is that the companies expect you to help onboard new employees AND do your other work at the same time, while at the same refusing to give you the time to build on a proper onboarding, with documentation to read, what software to install, etc.
In my current company we assign a "buddy" to the new onboarders, we have a handbook + a (supported and tested) onboarding installation toolkit, and pretty good documentation. The buddy does the handholding via scheduled and ad-hoc sessions, the onboarding material does the rest. During the pandemic we got to test this approach out on people who haven't even visited the office, and we improved it iteratively on every new onboardee. It's surprising how just improving such a small thing makes onboarding so much more pleasant for everybody, and how this, when done well, works both for office AND remote new employees.