Should I replace/change my helper? (Warning, long post ahead)

Hi all, would like to hear your comments/advice/feedback on my helper situation please. I had my 2nd child in Mar 23. Because of that, we hired a helper in April. We got a fresh Indo one coz we heard unpleasant stories about those with experience. The plan was for her to help to take care of my elder 2.5 yo son, clean/tidy the house and cook. If can take care of baby, even better, but if cannot also ok because I will take care by myself. We purposely make sure she come in 2 weeks into my confinement and when my confinement nanny was still around so that she can teach the helper how to cook and etc. When nanny was around, she just do housework and learn from nanny how to cook (no baby duties at all). My nanny left in mid April and it’s been 1 month since my helper cooked on her own. So far the food standards have dropped and been very inconsistent. I have also given her feedback on how to improve, taught her recipes and personally cooked + guided her few times but the standards vary. Sometimes it’s ok, sometimes it’s very bad and a waste of the ingredients that I’ve bought. It’s also the usual same few dishes, even though I know for sure my nanny has taught her more variety. I also gave her 2 cookbooks to read and learn but so far no indication of her wanting to cook anything from there. She also told me 1 day that she cannot cook and didn’t use to cook in Indo (though during interview she said she can but I guess they all say yes to get the job). My husband doesn’t like her food and will avoid if can. My picky eater son takes 1+ hour to eat because she only cooks rice and same old dishes. End up nowadays we have been telling her to cook less and eating out more (eg lunches) when the original idea was for her to cook both lunch and dinner. I also know she’s getting scared to cook some dishes because my hubby scolded her for the dropping standards and she ever asked me before if can don’t cook that dish. We knew she was fresh but didn’t expect she really cannot cook type. She didn’t even know how to cut apples until I had to show her 1 time. So now, all the fruits we cut by ourselves. If this continues, sooner or later, I foresee it will be me cooking and she just clean after I cook finish. To date, she still doesn’t take care of the baby at all. Doesn’t change diaper or shower baby because she hasn’t got the time to learn. She only carried baby a few times when baby cried and we were eating. She also doesn’t take care of my 2.5 yo son because for some reason he doesn’t like her. Could be becoz he is very attached to us but he doesn’t even want to play with her, let alone let her feed/shower him. We are also puzzled why he is like this (he didn’t have a problem with my nanny, in fact, he was playing with her after 1 week) but he has told me a few times (without valid reason) that he doesn’t like my helper. She do housework (wash toilet, vacuum, mop, wipe surfaces, tidy bed and wipe toys) and cook already take up all her time and energy (usually she wakes up 7+, afternoon nap 1h, rest by 9.30) so I also don’t know if she can cope and have no chance to teach her to take care of baby. Anyway, luckily we got a spot at IFC from July onwards so baby is taken care of. My conundrum is that overall, she is hardworking and her attitude is ok and she is courteous. She will always say she will do better but so far, the improvements are non existent/too slow and the competence is low. Now that she is only able to clean (also not perfect) out of the 3 or 4 things that I originally hired her for, we really don’t know if we should stick with her or request for a replacement from the agency (we are allowed to ask for up to 2 in the first 6 months). I am returning to work from my maternity in end June, so also cannot afford to wait a while more and see if she improves before deciding if want to change, coz also need time to guide new helper if need be. Sigh, really appreciate some 3rd party neutral view on this pls. Thanks much!