bought a new macbook pro 16" and lost all my Adobe paid softwares.

Tesserax wrote:

Apple does not allow downgrading to an earlier version of macOS than that comes on the device. Not sure how you were successful in downgrading it to Catalina.

FYI, While this is true most of the time, there can be an exception to this rule. If a specific computer model is released with macOS 10.15 and if this model has no hardware changes and is still in production at the time of the next OS release such as macOS 11.x, then that particular computer model can usually be downgraded to the older macOS 10.15.

alienista wrote:

Anyway, the question has an answer: don't buy a new mac unless you want to buy new software. Thank you.

You always need to check whether your apps are compatible with the newer hardware and newer operating system. You also need to make sure that you can transfer any existing software licenses for your proprietary software. Some proprietary software restricts the license to a single computer so if you want to move the software to another computer you either have to contact the software vendor to see if they will allow a license transfer or many times you need to purchase a new license. This is all the responsibility of the computer user/owner.

Also if you buy a pre-owned Mac from a third party vendor, then you need to be very careful that the vendor or previous owner has properly disassociated their AppleID from the laptop. You also want to make sure the laptop is not still being managed by a school or business. Plus you want to make sure the laptop does not have a firmware password lock enabled since there is no way you will ever be able to remove a firmware password lock if you don't know the password since you will not have the necessary paperwork to provide Apple to show you are the legal & legitimate owner of the used Mac.

Even if the used Mac doesn't currently have a firmware password lock enabled you need to be careful that you never forget the firmware password you use if you decide to enable the firmware password lock. If someone else uses your laptop they may even enable the firmware password lock without your knowledge. While you can still use the laptop to boot to the internal drive without issue, however, if you ever need to boot into any other mode (USB, Recovery Mode, Apple Diagnostics), then you will never be able to access those modes ever again without unlocking the firmware password lock.

At least purchasing a refurbished Mac directly from Apple you should in theory have the necessary proof of purchase if it ever becomes necessary to have Apple remove a firmware password lock. Just make sure to keep the original receipt.

Good luck.

Apple does not allow downgrading to an earlier version of macOS than that comes on the device. Not sure how you were successful in downgrading it to Catalina. Regardless, if you need an earlier version of macOS to run those Adobe apps, I suggest you consider using a VM manager, like Parallels of VMware to create a VM of the macOS you need, and then, run those apps in that VM.