Advice on what underwear to buy?

So I recently bought my first underwear. I chose a brazilian slip because I thought it looked cute and my have more space than other smaller slips. While I like how it looks on me, I unfortunately have too little space for my balls, they slip out of it. Which slips should I get next? Maybe something where my balls don't slip out lol but I still want it to be clearly feminine so no boyshorts etc, it should be some sort of slip. I also thought about getting a fufu clip to tuck myself so I could wear normal slips. Has anyone experience with them?

Also, I wanna get a top, I thought of a cropped tank top or a sports bra for my flat chest. Is that a good choice? I would like to get a "normal" bra, but I wouldn't know how to fill it except with silicone breasts but I can't afford them for now.

Also, which color? I wanted to go safe with my first slip and choose black. But I would like to feel more girly, more colorful, but I don't know what fits me. I'm white with dark brown hair if that helps. I have no idea what fits with that, maybe pink panties I guess? I just want more colors to wear even tho I'm not wearing outfits, it's just about the underwear (for now)