I had this problem twice, both of which required different solutions.
In 2018 I had this problem and the solution was to compile/export the application on another computer with newly installed/updated windows.
In 2020 the problem was repeated with another application and I solved it by deleting addons "even if the addon was not used in the project, it interfered with the app's performance!", Among other small adjustments such as collision, image size and even external JS libraries.
Each case is a case to be analyzed in depth.
Construct 3 is a powerful engine, 80 objects clearly shouldn't affect performance.
Even old smartphones that do not meet the minimum requirements can run an C3 app sparingly, I see it happen daily via playstore in my apps/games.
The best way to solve this problem is to debug and analyze the project and the computer of those who are developing it.