NextRadio Free Live FM Radio - Apps on Google Play
Lighting Wireless Speaker w/ FM Radio Compatible with Xiaomi Mi 9T, Mi Mix 3 5G, Black Shark 2, Redmi Note 7 Pro, Mi 9 Explore, Mi 9 SE , Mi 9, Redmi Note 7 (Blue) - Walmart.com
These are all the Xiaomi that integrate FM radios: so you can use it - Gearrice
Listen to FM radio on your Redmi 7 - Other Devices - Xiaomi Community - Xiaomi
Info about violet | LineageOS Wiki
Mix Fm
Redmi Note 7 is almost water resistant, but you should still be careful