*Simply regularly closing out memory leaks (browser windows that don't fully close) helps a lot!
*Helps with how much the processor gets bogged down, I mean...
And, better worded:
“I’d love to install a SSD as a 2nd drive, as I have a couple spares, but, I’m not at all sure the N22 has a spot for one of them.(?)”
D drive is usually the backup partition on MS Windows.....
Just get even a cheap ($2.93) USB adapter for the SSD, while Run diskmgmt.msc to see what it says, and from whence you can change the drive#.
Hope this helps. http://peacebyjesus.net
The tool you want is “disk management” to change drive letters, partitions, etc.
This is one of many sites the leads one to open it: https://www.howtogeek.com/787213/5-ways-to-open-disk-management-on-windows-10-or-11/
This machine is too inadequate* to be worth a lot of effort or expense
"It is as you say."
This here: https://support.lenovo.com/us/en/solutions/pd104074-product-overview-lenovo-n22-winbook, implies that it might have a smallish SSD. Might. And maxes out at 8GB RAM. And is extremely coy about exactly what CPU is in there.
Probably not a lot you can do with it. Mint Linux or ChromeOS Flex if you can tolerate the whole Chromebook experience.
Then back up what you want and whack it, factory reset. Problem solved.