Patching SSSE

Having read all the documentation about CUs for SSSE I am still none the wiser as much of what is written, in the many related webpages, appears ambigous, unclear and contraditory to me.

Could anyone clarify two points:

If, say,the December 2025 CU is installed, does it included all security and non security fixes for all features in SSSE?

Will Windows Update install the latest CE every month without any intervention including upgrading databases etc?

Thanks for any advice

ZD