First the bad news: compared to Astro/Dual Gap, 1v1 ladder will always require you to pay attention to more things at once, including micro. (Conversely, if you go from 1v1 ladder to Astro, it feels like playing soccer in a tight hallway.)
The good news: mastering the basics of the game can shut down these kinds of micro battles. Let me explain: I sometimes lose 1v1 games for the reasons you describe - unable to defend against getting stung in ten places at once. In those games, it feels my micro is inadequate, but here is what actually happens: I messed up my first two minutes (long power stall, or not enough factories, or slow to capture mexes). Now my opponent has 1. ten tanks more than me and can attack everywhere, and 2. I never got to push my opponent, so he can peacefully expand and focus his attention on attacking me. So: you’ll be surprised how much less micro you need once your macro is 25% better.
Now, if you still find the 1v1 experience too intense, try team matchmaker (TMM). Often the micro is a lot easier since you have only one or two lanes to fight in. I actually find the TMM macro much more demanding because, to play well, I feel I have to check what everyone else is doing and whether I should push my opponent or help allies defend instead. But I think most TMM players just do their thing and find it easier than 1v1.
If I was you, I’d just submit one of your 1v1 games to the FAF Discord channel “replays” and ask what two things you could do better. Lots of great players will give you clear, simple advice that will get you a long way.