Too many Sanboxes? PLEASE HELP !!

So for a project I got going on I needed to create 300 Sandboxes and use Google Chrome to log 300 different Accounts on a Website.

This is my dream and it was going AMAZING for a few days but after a week into this, something changed.

 

I used to be able to open 20 Sandboxes (20 Chrome Browsers) and it was going excellent, now I can only open about 8 OR LESS.
Seems like Sandboxie saves information? So everytime I open 1 Sandbox it opens like 5 more (Chrome Browsers) IN THE BACKGROUND making the PC too damn slow, multiply that by the 20 Browsers that needs to be opened.
And even if I close them one by one, they pop up back again automatically.

 

I need to have 20 open, I can't even have 10 now and because of this I can barely sleep, I am losing my mind over this. This is my dream and my job.

Now, can anyone help me to fix it? I could pay as if it was a Fiverr job, I guess.

Do I need a better version of Sandboxie?

Is there a Sandbox program that does not cause this?

Is there a way for Sanboxie to stop saving data... just my session logged in?

Is there a different program that can log 300 Accounts on a Website? (and keep them logged in, one on each different Browser)

Any other solution that you can think of?

Before you suggest that I need to delete the contents of the Sandboxie so it won't have any data on it:
1. Didn't work, maybe it's not about THE Sandbox, maybe it's because I have 300 Sandboxes.
2. Regardless, this is unacceptable too, because I would have to log the Accounts every single day and that... besides time wasting, is also impossible to log 300 each day.

Any comments that could be useful?
I appreciate your time, thank you.