How to remove very irritating LOCAL Temporary tablespace in 12.2 or 19.18

hi, afternoon everyone.

Made a big mistake and implemented Local Temporary tablespaces before realizing the implications, namely, that as they are BIGFILES they are hard to manage.

Smallfile temporary tablespace TEMP is the default temporary tablespace

Bigfile Local temporary tablespace LOCAL_TEMP is the default local temporary tablespace

I have reset all schemas previously using LOCAL_TEMP as the local temporary tablespace to now use TEMP, so all users will be using TEMP and TEMP instead of TEMP and LOCAL_TEMP.

The PROBLEM and it's a big one. SOMEHOW i managed to set the off-limits schema XS$NULL to use LOCAL_TEMP, but now i cannot reset this schema to use just TEMP.