Mint 20 fresh Install and short on memory?

My Mint 20 Install went ahead beside Mint 19 from a year ago. But it only got 26 GB. The partitioning was automatic. But I after installing some software got the warning I had 16 Mb left. I have Gparted and looked in, I found the 99 GB used by Mint 19, and two partitions the same size and my Mint 20 26 GB space. Is there a way to change this, or do I need to wipe Mint 19 to do so?

Before I lose Mint 19, I'd like to try to get my favourites off the old Chromium browser. Although in Mint 20, Chromium Browser is installed but is not found in the Internet list to start up.

I am thinking of replacing Mint 19 with Neon.

Should I wipe the SSD with Gparted first?