See my link from Post#1378 https://forum.xda-developers.com/t/rom-unofficial-aosp-android-7-1-2-nougat.3471350/post-84385521
Or other before than you can find the working links for all SW Versions.
Thats what I posted in previous post, use alternate Apk Stores, Apk pure or other.
Install magisk from decatf and than install KernelAuditor for OC the CPU to Max 1400 MHz to give this Tab more performance .
Install decatf's magisk version for Root and than KernelAuditor Apk .
Over clock the CPU to Max 1300 MHz.
After some reboots than you can update magisk to newer Version.
Search one YouTube " how to install TWRP on Galaxy Tab 8.9 "
Than you can follow it step by step.
Important is that you now the steps to boot to the Recovery.
Important 2
You need TWRP 2.8.7.0 and Odin 3.07 , not newer Version.
Also enable developer settings and USB debugging.
At is all OK , its up to you if you want to do this and I like your work what you have done on this Build for our Tab..
And This Build is for me full use able.
I tested all your ROMs now from the first Version.
For me it is full functional and I can use it as daily drivers.
Some times my browser crahes ( I use opera mini in private mode with VPN )
In the moment I try to find some setting were the crashes come from.
But that is not a main problem...
Which Type of S4mini is it LTE / 3G or 2 Sim
Have you make an clean install / factory reset , wipe cache and dalvik / data / system and if you all files on an ext. Sdcard also data media ( into.Sdcard )
Make sure that your phone have the correct TWRP installed.
Was your Sim at flash time...