GLPK or GLPK_MI? GLPK is probably the worst tool you could pick. I tried it before on some of my problems, and it would not ever finish. Use OR-Tools, if it will work for your problem, or maybe one of the other free solvers with CVXpy will help you (https://www.cvxpy.org/tutorial/solvers/index.html), if you really need a free tool.

GLPK should not be used as a guide for the general field. The commercial solvers will do infinitely better than GLPK.