Have a look at this forum post. This problem is not new with Windows 11 and has been experienced by a number of users as the post shows.
Hello all Computer: XPS 8940, 10th gen Core i9, Windows Pro 11   Upon the installation of Dell Support Remediation (or something whose name was close to that), I started to see a massive memory leak in LSAAS.exe (Local Security Authority Process) .. It started a few minutes after bootup and in 20 minutes (there abouts) the leak was up to 20 GB (Fortunately I have 64GB of RAM) .. Removal of the Remediation stopped the leak and upon a reboot, LSAAS was back to where it should be.   Has anyone else seen this?    
Dell Support Remediation seemingly caused a LSASS memory leak under Windows 11