Hey OP! :)
I know this post is from a while back, but I just wanted to come by and let you know that we have now increased the Construction limit 10 times since it was introduced (in Season 3).
We had the limit in place due to technical reasons and ensuing the game experience stayed smooth, but our team has been at work to make that limit less restrictive. We're hard at work at increasing this limit even further!
You can read more about our most recent update here: https://store.steampowered.com/news/app/858820/view/3726209391905730306