This is really hard, I think this is a really strong character design and all the design choices you've made suit the character, but I do see what you mean with her feeling less 90s computer game-y. I am probably least familiar with 90s fashion design aspects, but I have played a few 90s edutainment games as a kid so I can try and give you some tips but I don't know how helpful they'll be haha
I feel like if you want her to get that 90s kids edutainment game feeling you might have to push her design in terms of colour, but I like her colour scheme as is and I think she works as a good contrast to the other characters in the world, her more muted colour scheme works very well with the old computer look and (I assume) the more nerdy vibe of the character. I do really like her design, the only things I can think of is: maybe the pants, they look a bit more alphabet themed rather than keyboard but I'm not too sure how that could be fixed since they're about as close to keyboard pants as you can get, also 90s pants were a bit more wide-legged than flares so maybe change the shape a little bit, a lot of more casual pants were cuffed so you might want to try exaggerating the cuff size/width on the pants she's got, and maybe the tie? I do like the colour and I think it works well with the headband, buckle and shoes, and again the colours work really well together so I recommend keeping something there plus the tie does work well with the more nerdy theme, but personally neckties like that make me think more 70s or 80s rather than 90s, a necklace or brooch could work, or maybe change the shape of the tie, the little hourglass loading symbol could be cute as a bowtie. Playing around with her skin colour could help a lot in the computer game aspect, a more unnatural colour could work, personally I think a blue, light cream or grey skin tone could work well with the 90s computer theme but I'm not too sure which one would work best with her current colour scheme, I don't think you should worry about changing her skin tone to something unnatural given the colourful world she exists in I think she would still read as being human despite being blue or grey or whatever colour you go with. Maybe her blouse could have a faint/light grey pattern over it like a wire frame, lines of code or a checkerboard on it to add to the computer theme, but that might overwhelm the cute keyboard pants design, which I think is a strong design choice you should keep, the last thing I can think of is maybe make the buttons on her shoes and sweater vest square instead of round to match the pants and glasses (The Clippy glasses are very cute).
I can see that the other characters in the universe have a lot bolder styles, I like the contrast she could bring to them, she might stand out a bit, but also early computers did have that simplified look to them so I don't think you should feel bad that she's less detailed or vibrant than the other characters. Overall I do think she's a very well designed character