Try creating a new user and test if the same behavior applies to it. A new user profile comes with a clean CurrentUser registry hive (a db file containing a lot of program settings) and less added extensions which apps usually install for current user (the user profile with the issue) while leaving other user profiles alone.
If the issue happens on the new user as well then the issue might be hardware related, mostly random reads/writes, RAM failure, HDD failure, mainboard failure, cable failure. The best you can do is to defragment the HDD / secure erase the SSD (first backup the OS using a full system imaging software like TrumeImage, TeraByte IFW or alike, then secure erase the drive - this will reset the SSD's data structure to unprogrammed, like it were new, then restore the backup). This does not guarantee fixing.
If the new user profile has no issues creating folders fast, then you'll have to look at several other places.
Use Sysinternals Autoruns utility to disable any unnecessary context menu handlers, by unticking them. Look for *...\ContextMenuHandlers under the Explorer tab in Autoruns utility, which are the ones applied to the surface of any folder, when clicking empty space and subsequently loading all components when all that is needed is the New -> Folder entry. If components are the cause, the New -> Folder entry should show up quickly.
If this doesn't fix the issue, restore the components by ticking them back to their initial state. If the are unticked from the start leave them so.
User Nirsoft ShellMenuNew to disable new context menu handlers, works on the same principle as Autoruns.
If this doesn't fix the issue, restore all of just what you need.
Try looking at registry's BagMRU entry, it's the place where every time you open a folder it creates its settings and views as setting strings in the registry.
It's an immense fup on ms part, and over time this thing becomes about 1/2 of the registry's size. This usually also slows down folder browsing, if once cached when accessed for the first time in a session it won't affect viewed folders later, unless it gets uncached by the explorer.exe process.
Open the registry (run > regedit, or use something like Registry Workshop application), navigate to:
You can delete this whole key, but export it first as a backup (right click, export, give it a name, save as reg).
The only thing you need to recreate is the Key BagMRU and the size value "BagMRU Size", a DWORD of whatever yours is, mine is a 5000 decimal. Everything else will be recreated once you'll browse folders, but you'll lose current folder settings (views and icon sizes).
For noobs, recreate a blank BagMRU key:
have Shell key selected in the right tree layout of the registry, right click new -> key in plain area on the right of the tree, give it the name BagMRU instead of New Key #1 and press Enter
have BagMRU key selected in the right tree layout of the registry, right click new -> DWORD (32-bit) Value in plain area on the right of the tree, give it the name "BagMRU Size" without the quotes instead of New Value #1
double click BagMRU Size, select radio box Decimal and enter 5000 in the Value data: field.
since you're noobs, a good way to see if all worked fine is to logout and login again, if the new folder procedure works fast then that's where the issue was, if not kill main explorer from task manager and re-run explorer.exe.
If you can't figure it out, but did export the old one, find the reg file and double click it to add its contents back to the registry.
The unlikely but still could be the issue - antivirus application (AV for short) on slow/old systems.
Try lessening AV's scanner settings, less heuristics at first, test with and without "on creation" event, if it allows so. If not, then probably it's not it. This one doesn't come with detailed instructions for noobs because you need a medium level of understanding what these settings are so that later on, if a wannacry trojan hits you, you won't complain that the guy on superuser said to do it leaving your system vulnerable. Best is to ask the windows guy next door for help.