Nandroid first. This way you can try on rom of choose to test.
Instructions for Settings with transparent background:
1. download settings.rar and extract the apk inside to your sd card
2. copy or move the apk using root explorer
3. navigate to system/app
4. tap on r/w at the top
5. [optional] backup your Settings.apk/ somewhere just in case it doesn't work for your rom.
6. paste all apks
Phone: Htc One Max T6VZW
Rom: ViperMax 1.0.1
Theme: DarkMax 1.0.3 & Team Black Out
Recovery: Venom's TWRP