Don’t disagree for the “properly drafted” part…it’s just that so many smaller businesses can’t afford to spend thousands on a lawyer, or can, but simply think they can use an existing one and “modify it themselves”.
And, at least in my practice over the past forty years, I’ve dealt with WAY too many oral agreements between parties. Legal, notwithstanding that they’re oral, but impossible to validate unless there are third-party witnesses. And, of course, oral agreements generally end up in misery for one or both parties.
I’d almost prefer those to the DIY ones that make a complete hash of the law, be it commercial or more usually,“contractor status” employment (“you are not an employee, but you’ll do everything on my schedule, my way, using my space and tools and I’ll give you some payment”). Oof. How many different federal and provincial laws can we transgress in one agreement?
Back to the original point: sadly, too many arrangements are made in small biz without professional guidance, and that is actually the root cause of most of these issues, giving us grey hairs because somehow WE have to make a decision like the one the OP faces.