Indeed you can get info from export but do NOT simply import the entire export. That will fail and/or cause problems.
Do a /export on the old router, read the file into a text editor on the PC and prepare the new router with the info that
you need to add manually anyway, then paste the sections that refer to hotspot, user manager etc. into a telnet/ssh
window to your new router.
Remember that references to interfaces only work when the interface with the same name exists on the new router.
You will either have to rename interfaces or edit the export on the PC to have the correct names before you cut/paste it.
Don't do to large sections at once, but do sections or even lines at a time.
And remember what you cut/paste this way is only ADDED to existing config, so when your default config already has
some lines in the section you need to delete them first or manually adjust them.
To summarize: it can be done but you have to understand what you are doing and be patient and careful.