How can I get my recovery back? I was trying to get TWRP on my Asus Zenfone 2 ZE551ML (Stock firmware, WW-2.20.40.198). In order to do that, I tried to unlock the bootloader using this guide. I don't believe the unlocking really worked, though, because every time I tried to flash TWRP through Fastboot or the app, it failed.

It did, however, lose me my stock recovery. If I go to the bootloader and select "RECOVERY MODE", the phone just restarts and goes to the same bootloader again. So I got neither the stock recovery, nor TWRP.

As you can see from this answer, the only way I know how to flash stock firmware is through the stock recovery.

I did manage to root and install Xposed, though, both through adb. What worries me, though, is that if some root app or Xposed module mess up my phone somehow, I won't be able to flash stock firmware or a backup. So I really need a recovery. I would actually prefer to have the stock recovery at this point.

What can I do? I need the stock recovery to flash the stock firmware, but I can't.

I've tried Asus Flashtool before, but it didn't work. I think maybe it's because I tried it on Windows 10, some users said it worked better with Windows 7.

How can I get my recovery back?
You can flash the stock recovery through fastboot. The complete guide for flashing is here