How do I deal with a trade that became mostly paperwork?

You can price any job accurately, and you are worn down by discovering how much of the trade turned out to be paperwork and math instead of the craft you came for. That grief is real. You signed up to build or fix things, and a large part of your days went to numbers and forms. It is fair to mourn that. But the paperwork is not separate from the craft; it is what lets you keep doing the craft as your own person rather than someone else's hire. The estimating you resent is the very skill that gives you control over your work and your pay. It is the tax on independence, and it buys something worth having. If the balance has tipped too far, do something about the balance. Hand off, template, or tool away the parts of the paperwork that do not need your judgment, and protect real time for the work you love. You do not have to enjoy the math. You just have to keep it from swallowing the reason you started.