@RareBreed start with Old Navy for some work pants... they have these super comfy "Pixie" pants. Usually they have like a slim ankle cut, but also carry boot cut/flare etc. You can at least try them on in store and order the preferred style online (I know, not ideal...but our location just isn't always stocked with all their styles). These particular pants are super comfy and flexible and come in standard colors, plus some fun patterns. I consider them a great work wardrobe builder. I've bought them in many sizes and colors over the years in all my various gains and losses and they are always flattering, no matter the size. I particularly like that they offer petite/short since I am just that....short.
As far as tops, again stick with basics as you build. I've bought several sets/3-packs of plain v-neck tees on amazon and pair them with cardigans I find in Marshalls/TJ Maxx. That dresses the basic tees up a little since I hate "blouses". I have some of those but I prefer a simple cotton tee and dress it up with simple jewelry and cardigans.
Not sure what you're allowed for footwear, but I just got these for the summer and you'd never know they're crocs. They are so cute and comfy!
https://www.crocs.com/p/brooklyn-buckle/207431.html
don't overthink it too much! And don't feel pressured to buy patterns and colors that you wouldn't normally wear at home or they'll just sit in your closet for 10 years, ask me how I know

I've curated my own work "uniform" over the years: small wedge or mule, slim ankle pants, plain tee and nice cardigan, repeat Mon-Fri. I'm lucky enough I get to wear jeans nowadays but when I need to dress up a little for a special meeting or whatever, I just swap for my Old navy pixie pants. I never find nice pants at Marshalls/TJ Maxx, but that's just me. I see them they're just not normally my size/style.