Firefox portable for stealth google ads account

Has anyone tried firefox portable for creating google ads account?

You can use it for a single account but it's not the best solution as not that many people use Firefox and in general you should do your best to blend in, but if everything else is done correctly you can use Firefox portable.
However, if you're hoping to use multiple profiles on one computer for multiple accounts, Google will be able to link them by your hardware properties. You can avoid this by changing some settings in about:config but Google will know and it will be a minor red flag.

Better option is to use Multilogin or an alternative. If you don't want to pay for that, use different profiles on different devices.

Yes it works fine, just that you need to manage your fingerprints well.
Also you need a clean residential IP to make google ads accounts