I have worked in companies of various sizes, from (currently) running my own startup, to leading teams in rapidly growing startups, to a cog in the engineering wheel at Google. From (currently) fully remote, to having some team mates working remotely and others on-site, to fully on-site.
I have never found the particular wiki/document tool we were using to be even close to a critical factor in the onboarding process. Onboarding works well when experienced teammates are given the time to show their newer colleagues the ropes. It works poorly when there is no personal attention given and people are just asked to go and read docs and left to their own devices.
My sincere recommendation to anyone starting their own business is to stop wasting time, money, and energy on decisions like these which do not materially impact anything about your business. If you're using GSuite, just use their stuff. If you're using Microsoft's equivalent, use their stuff. Otherwise, JIRA + Confluence are free for small teams. Otherwise, if you're already paying for GitHub, Gitlab, whatever, just use their tools.
Last thing you need to do is spend an additional $8/team member/month for functionality you are already getting for free in other services you are using. Believe me, it will not make a difference to your likelihood of success. These decisions are just procrastination traps which distract you from the important stuff - talking to users, talking to customers, and building things they need.