https://smile.amazon.com/dp/B07MZDNBDJ/ref=cm_sw_r_cp_apa_fabc_.aB3FbPDMTFE0
I'd get this dumb phone (or something equally cheap) and stick her simcard into it.
When she pays you back for the replacement /repair +the cost of the dumb phone you can explore giving her a smart phone again.
NTA - Also, you can search for ways to "child proof" a phone.
Even better, get them a dumb phone for $15, where they can call and text, but forget Reddit and anything else.
I would think an unlocked BLU phone
https://smile.amazon.com/dp/B07MZDNBDJ/ref=cm_sw_r_apan_i_BB745VF562C3QDN7J5QP
This one has Android 9 (and possibly upgrade to 10), is cheap, and humiliating enough for teenager.
https://www.amazon.com/BLU-GSM-Unlocked-Dual-Black/dp/B07MZDNBDJ/
https://www.amazon.com/dp/B07MZDNBDJ/ref=cm_sw_r_cp_awdb_imm_7NVJTZ28WS5BH2S51QQN
This is a really cheap model. You can also get more flip phones
BLU Z5 -GSM Unlocked Dual Sim -Black https://www.amazon.com/dp/B07MZDNBDJ/ref=cm_sw_r_cp_api_glc_fabc_mR63FbVJCGWD4