Alright, here's what I'm going to do. A lot of the improvements I'm going to suggest boil down to "just play better". I'm going to write these in cursive so that you know they are possible, but might demand more of you. Anything not in cursive is something you should be able to act on by just knowing it, instead of taxing your apm and the like.
First of all, you're too slow to expand. The AI is perfectly beatable this way, but ideally you'd be keeping on pace or ahead of the AI in metal extraction. Having every mex covered by 1 llt is enough, you don't need to build a forest. Catch bigger raids by moving your army to the radar dots.
If you're going to beat the AI while down in economy, you have to prepare accordingly. You will not be able to beat down their front door, and will have to outscale them using fusions and converters. Any favourable trades in the meantime are welcome. This means you do not need to build more army than it takes to defend. Either cut back on the amount of pit bulls you're producing, or the amount of t2. Invest into fusions instead. After the first few fusions, switch to Advanced Fusions. These are very explosive, so build them in the back corner.
The army control needs work. Have separate hotkeys for long-ranged and short-ranged units. Move them accordingly.
Alternatively, switch to single-unit compositions. Build only hounds, or only welders, you're having trouble managing both. Have sharpshooters behind the lines, but waaaay behind, not in the same blob. Sharpshooters don't have to be moved as often.
Don't stop scaling the economy, make sure you have fusions always queued towards the lategame. If you don't want to think about it, literally spend 30 seconds setting up a queue of afus-4converters-afus-4converters.... like 10 times.
Dont's neglect resbots towards the lategame, keep them active. If it's a good unit, it often makes more sense to resurrect it instead of eating it, especially if you're going to hit the overflow.