Phoenix Jailbreak -

Choose "use provided offsets." If the device restarts and Cydia does not appear or crashes, open Phoenix again and tap "Kickstart Jailbreak".

Can be done without a computer by downloading the Phoenix IPA directly from its website. Phoenix Jailbreak

The jailbreak deactivates upon device restart, requiring you to reopen the Phoenix app to reactivate it. Choose "use provided offsets

On your device, go to Settings > General > Device Management and trust your Apple ID. Phoenix Jailbreak