Unavoidable problem or not: lack of understanding contract terms offered by prospective customers that prolong the time to negotiate compromises and ink a deal.
If this unavoidable but necessary for you as a cofounder to solve, would you hire an attorney or use a software solution to explain what the terms mean? If the latter, what are options (if any) and what gets you comfortable to use the software?
The assumption your startup's paper is not an option because your customers push their own paper with all suppliers.
As someone who does a lot of startup contracting (focusing on SaaS, but not exclusively at all), this is a bit surprising. Most of my clients use their own paper most of the time. Large customers typically push their own paper. Smaller customers don't.
Candidly, getting an explanation of the terms in a customer's version of a contract is insufficient. It's not just about what's there - it's equally important what's NOT there.