@ETFreeman What you are saying is how can I defeat my guncom opponent without upgrading my own com? Units only?
This is kind of a silly decision, but it is however possible. The real logic table for bread and butter play is gun com and prevent turtle, or turtle and prevent pushes from your opponent and beat them into t2 arty creep. If you are ruling out these two very very very standard options, you will need to simply outnumber them
The build you need calls for mass factory drop and t1 tank/ arty spam. You will also need to essentially feign defeat when he comes in with his gun com and let him move forward some, then having built up numbers from your large number of t1 factories, run him over with your units and just keep your com out of it, or mopping up some back units (its severely outranged).
T2 units die to quick to oc so just use numbers of t1 and a bit of surprise to catch him off guard. Again I emphasize the need to let him "win" some and lose only a few units while getting him charging recklessly forward, then go in for the kill.
No guarantee you'll polish off the com here, but you can beat that timing just by backing up just a bit and swarming.
Really though, use the main two options the most. They have higher success rates.