Amazon.
Specifically this one
Women's Dry-Fit Golf Polo Shirts... https://www.amazon.com/dp/B012U0OVR0?ref=ppx_pop_mob_ap_share
It's the only one I've found that isn't super baggy on my small chest. Love it.
They sell sun sleeves and sun shawls hat are real lightweight material for like surfers or beach goer's or golfers to wear. I have some that I used to cover my cuts and scars nd still use now that I have tattoos over them cause the sun is not good for tatts.
4 Pairs Cooling Shawl Arm Sleeves Sun Protection for Women Men with Finger Hole for Golfing, Driving, Riding, Fishing https://www.amazon.com/dp/B07STVCX3V/ref=cm_sw_r_awdo_navT_g_KT7QAN9Z65J7NQB3ZVC3
I used to hate the tan line until I realized that was how other cyclists could recognize me as One Of Them. :D Now I just lean into it.
I draw the line at jersey tan lines, though. I just bought a pack of these for summer rides (I hate sunscreen and I tan through it after a few hours anyway). I have some of the normal arm-only ones, and they work well (and they're cooling!) , but they don't stay up over my big guns. I'm pretty excited to try this style.
Eh. It might be useful, but I really don't like the "tactical look". Also my work requires business casual dress. I might actually be looking at a shoulder holster, but drawing one looks to be a little more complicated than an IWB appendix holster. I was looking at this Aker Leather belt. For usefulness without looking like it's anything more than a leather belt.