OP I know exactly where you are coming from, you find your DD1 difficult in just the same way my DDad did my younger less academic DSIS.
You need to step back, relax and let her be, what she will be. Offer help only when asked and only as much help as is asked for, don't turn every simple maths and science question into an hours lecture. Know when to shut up!
My dad was bad at this, DH is absolutely dreadful, imparting every scrap of knowledge you have on a subject up to degree level to do Y5 homework is not helpful.
If you live and breath science yourself it's very difficult to remember most people don't. I guess, you like me, DH, my DDad and DD1 needed, from birth, to understand how the world works. Not everyone does, some strange people need to understand other people and social interactions, not science. It's very strange.
DH and I will always find the fact that DD2 finds other people fascinating and science a bit dull very peculiar. (DD2 can do the science, maths, English etc, because she is genetically very clever, but DH will always be puzzled by her just doing things without a zeal to know more. He doesn't get she needs head space for clothes, pop music, friends gossip and all the rest of ordinary life).
My DSIS hated school, she never found anything she particularly liked and left at 16 with a handful of CSES. Only having worked for a year in a shop, did she go back to secretarial collage and discover she could type and get her head round the earliest, horrible word processors.
At last there was something, other than spelling, she did way better than me. Over the years she's worked in varying admin roles and taught herself a load of computing skills both software and taking the things apart to upgrade them. The common sense she lacked as a young teen, developed with time and the need to use it.
Dear OP your DD needs love, and space to develop into who she is destined to be, please give it her.