I was talking to a friend about this who played SC2 for years but couldn't help being annoyed about all the mechanical aspects of BW.
Initially I offered up the cope of "you'll get used to it lol", but upon further reflection I realized that for me there was never a moment where I had to "get over" these aspects of the game. I always loved it due to the fact that I had first experienced it as a child, so it has forever been my baseline for how an RTS feels.
So in short, if you are struggling with it then I just don't think its the game for you. I think there are aspects of Brood War that are massively smoothed out by nostalgia. Now that's not to say the entire playerbase is helplessly blinded by nostalgia, but I do believe there are certain aspects you need to be "primed" for.
For example, if you don't get EXCITED at the prospect of mastering the control of units through the restriction of the 12 unit selection limit, you are going to be stuck eternally seething about the outdated interface. Similarly, if the concept of muta micro doesn't excite the fuck out of you (and you instead find yourself thinking, why can't this happen automatically) then again, you're going to have a problem. And similarly for manually setting workers to mine, mastering camera hotkeys, spellcaster control, dragoon pathfinding (actually fuck those guys for real), etc.
As someone who grew up with the game, seeing all the efforts the pros go through to get around the in-built limitations is a never-ending source of fascination. Nothing is granted for free, and for that I find the game cool. But to someone else it might just be absurd and annoying, and I don't think of them as a "lesser gamer" for feeling that way, its just a matter of personal background.