Brand New MacBook Pro is running Catalina, but I need Mojave

Hi, Everyone.

My name is Andre.

I would Truly and Greatly Appreciate Community's help with Information that would steer me in the right direction and ultimately would prevent me from waisting money.

I'm NOT a computer savvy person and not always understand or able to use technical computer terms/language.

But, I'll do my best to describe what I'm looking for.

After owning and using 2012 model of 15 inch MacBook Pro for 8 years, I feel that my machine gotten very sluggish and in some instances painfully slow, especially during booting up and opening some apps.

Recently (July 2020), I've decided to start shopping for a 0-2 years old model of MackBook Pro and I'm aiming for a Brand New, never opened machine. Most likely that machine's OS will be "Catalina".

My current MacBook Pro (2012 model) is running "Mojave" and I want to stay with that OS.

About 6 month ago I regretfully upgraded to Catalina and I had to revert back shortly after (with Apple Support technician helping me on the phone).

I'm not claiming that there was something wrong with actual new OS. But for me, Under Catalina I've lost some important functionality and features that I would normally use daily under Mojave.

So, here is my question: is there a way to install/use Mojave on my new machine which most likely will be running Catalina?

And if "Yes", are there any tutorials, videos, step-by-step instructions that would help me to get it done?

Remember: I don't know what's going on "under the hood" of laptops (like "code", "command", etc.)

I'm looking forward to Your suggestions and I THANK YOU in advance!!

Andre.