"Sony will patch this tomorrow." Reality: Sony abandoned the Vita in 2019. The "new" 3.74 exploit uses a hardware flaw in the GPU driver stack. It is unpatchable via software updates because Sony can no longer release software updates that change the core bootrom.
You can no longer create a new PSN account directly from the PS Vita system. New accounts must be created on a web browser or a newer console (PS4/PS5). Disabled Account Management: ps vita 374 firmware new
If your system is below 3.74, you can update through these methods: System Update Update Using Wi-Fi PC (Content Manager) : Connect your Vita to a PC running the Content Manager Assistant and select Update by Connecting to a PC PS TV Safe Mode "Sony will patch this tomorrow