Well done the difficult bit is done! You have successfully installed TWRP.
What should I do next?
Stop and reflect!
You can perhaps now install /e/ by SD card there may be a hazard! If the phone was on Android 10, Easy Installer had it in mind to downgrade that in preparation for Oreo (8) stable. Check the log as mentioned above, did the downgrade happen? If you install manually you must install the same Android version that is recorded as being on the phone - we were already told there was no OS, so Android 10 is likely wiped.
Only if you decide it is definately safe to change to manual at this point read [HOWTO] Install /e/ on a Samsung smartphone with Windows easily
To be safest I would stay with Easy Installer.
Edit. Also worth exploring the reboot options in TWRP if you are not familiar with it. Reboot to system, there is no system, will return to TWRP Recovery again. You should be able to reboot to Odin mode if you need to from TWRP.