Installation of unofficial ROM on Lenovo tablet doesn't finish and device is unusable now

I have an old Lenovo tablet, device model is Lenovo Tab4 8 Plus (TB-8704x). Since it stopped receiving updates after Android 8.0, I wanted to install a more recent version of Android from unofficial builds available. I have gotten the ROM from following two sources: 1. Pixel Experience: https://xdaforums.com/t/rom-unofficial-10-0-pixel-experience-10-for-lenovo-tab-4-8-plus-tb8704f-x-n.4221955/ 2. LineagheOS: https://xdaforums.com/t/rom-unofficial-10-0-tbx304f-l-x-lineageos-17-1-for-lenovo-tab4-8-rom-for-the-lenovo-thinkpad-tablet.4259205/ . I have a vague memory of the setup step so I grabbed a few ROMs and compatible TWRP, then I followed the following steps: 1. Unlock the boot loader from Setting and enable debug mode on device. 2. Unlock the bootloader using command fastboot oem unlock-go, or it was fastboot oem unlock. I don't remember which one worked exactly but one of these did the job. 3. Reboot the device in fastboot mode and flash the recovery using following command: fastboot flash recovery twrp-3.2.3-0-tb_8704x.img. Probably a mistake. Its not required since you can just boot a custom recovery which I did next anyways. 4. Boot into TWRP using command fastboot boot TWRP-3.4.0-0_TB-8704X.img. 5. I wiped Cache and Data from Wipe > Advanced Wipe menu in TWRP. 6. Already inserted was SD card with ZIPs of ROMs above. I selected Install menu and selected only one of the ZIP files to install on my tablet. TWRP installation screen stays there for hours and installation doesn't finish. I tried with other ZIP as well and same result. On normal reboot of the device its stuck in boot loop. What can I do to fix this? foersn