[Security Help] Fell for a fake "Windows Update" trick. Worried about a persistent Trojan/Rootkit.

(Post this text below)

Alright Reddit, I messed up bad and need some advice on system security.

A few days ago, I was browsing online when a pop-up appeared that looked exactly like a real Windows Update. After about 30 seconds, it told me to press Windows + R, open a directory, and paste in some command.

Like a total moron, I did it without thinking. A second later, the "Oh, crap" moment hit me: Windows never asks you to randomly paste code. I was stuck in the browser window and knew I was infected.

The Cleanup

I immediately ran Windows Defender (Quick and Full scans). It found and purged a bunch of files, but one file was extremely persistent and kept protecting itself, even in Safe Mode. After multiple tries, I finally ran Malwarebytes, which seems to have fully purged the infection.

My Concern

My main concern is what might have been left behind. The malware that ran was clearly aggressive, and now I'm paranoid about a remaining backdoor, rootkit, or keylogger that my scanners might have missed.

My Questions:

1. Is it possible for a rootkit or backdoor to survive scans from both Windows Defender and Malwarebytes? What are the chances I still have a persistent infection?
2. Given this, what are the next technical steps to secure this machine? Is running these scanners enough, or is the only 100% safe option to format the hard drive and do a clean Windows install?
3. How can I better protect my system from this in the future (besides not pasting random code)? Are there other tools or system settings (like running as a standard user) that would have prevented this from executing?

Feeling pretty stupid and paranoid. Any and all technical advice is appreciated.

TL;DR: Fell for a fake Windows Update pop-up that had me paste a command. Ran Defender and Malwarebytes and removed a persistent file. I am now paranoid about a remaining rootkit/backdoor. What are the next system-level steps I should take to ensure my PC is 100% clean?

I used gemini to edit the post to improve grammer