DO THIS AT YOUR OWN RISK!!!
I would start by turning by guest account to a google account. (Using a guest account Is never a good idea, no matter the game)
Assuming I don't have access to the game anymore, I would install an original version of swgoh (unmoded) apk (just google it) and try to install over. If this didn't work (probably) I would take an educated risk and just uninstall my current version and then use google play store to install the original swgoh version.
Why "educated"? Well, some time ago (can't remember why) but for some reason I wanted to force-start a new guest account and In my emulator no matter how many times I uninstalled and installed the game or version I used, it always started the same guest account.
After some research, I found out that the games ID was linked to my emulator device (or something like that. I really can't remember.). The workaround was to (in phones) do a factory reset or (in emulators) create a new instance/VMs.
With this in mind, you should be good IF you don't change anything in your device or emulator.
After this I would follow the instructions in the 7th post of swgoh forum
here:
Only after succeeding doing all of this, would I try to install the mod.
The sign version requires facebook login. The unsign version can use google account but requires root.
Best of luck!