Simply to upsell Microsoft feels the need to basically switch off components within its Windows OS (Operating System). Annoyingly the real-time protection feature keeps enabling itself every time Windows is restarted. You have a few ways to switch this off, but my personal preference has always been the group policy method, however using Home editions this is missing.
You can use this method to enable it:
How to Enable the Group Policy Editor on Windows Home Editions | TechSpot
Or slightly different way:
How to Access the Group Policy Editor in Windows Home
There does seem to be an alternative method to Group Policy called Policy Plus, but I have not tried it out completely to comment. You can find it linked below.
GitHub – Fleex255/PolicyPlus: Local Group Policy Editor plus more, for all Windows editions
Turning off real-time protection permanently even after restarting.
Turn On or Off Real-time Protection for Microsoft Defender Antivirus | Tutorials
Having a look at the very first and second links I shared should also provide you with useful things to switch off/on. Like disabling telemetry.
For your information: Microsoft has slightly changed some things so they may be worded differently. Such as Windows Defender is now called Microsoft Defender so older guides may not reflect that. Tamper protection needs to be also disabled.