[LineageOS Questions & Answers] Jaqueek:
note: everything that I've flashed was from my SD card; I had the files on /sdcard1/Download

note 2: since my device's bootloader is unlocked, I have to press the power button after turning on the device, so that the "bootloader unlocked" warning goes away

I've managed to install TWRP (I followed this guide, "How to Install twrp Recovery on Samsung SM-T295" part, I modified a bit the steps, i had to go into download mode again after flashing TWRP_3.4.0.1+vbmeta_T295.tar and flash aboot_vk_T295XXS3ATB4.tar) and then LineageOS 17.1 (from a GSI I found on this post, to flash I followed this guide) on a Samsung Galaxy Tab A 8.0 (2019) (SM-T295). Then I rooted it after installing LOS (from this guide, "How to Root Samsung SM-T295" part, I didn't make a backup due to errors, and multidisabler-samsung-2.6.zip failed to flash). Magisk had to update after, so I did that. Until then, no errors, until I downloaded BitGApps (I followed this guide, I downloaded the ARM64 version for Android 10 directly from my device). My TWRP had some problems flashing, because I couldn't access the Internal Storage from there (for some reason, /sdcard directory shows only folders on Install (and files, in the file manager) with random numbers and letters names like MAKVjaaw24Ajg35waD (not an actual folder or file, just an example), and I couldn't find the files to flash, which is why i had to flash everything from my SD card), so I rebooted to system from TWRP, and tried to copy the BitGApps file to my SD card so I could flash. I think I was about to copy the file (or I had just selected the copy option but hadn't found the directory to copy the file to, which was /sdcard1/Download), and suddenly, my device just powered off. I thought "oh it's just a bug, I'll power it on again and it'll be fine", but something strange happened when I powered it on; Now, every time I turn it on with the power button, I have to hold it less time for it to boot for some reason. That's weird. When android started and I could use the device, I tried to copy BitGApps to my SD card again, but my tablet powered off again and the same happens every time now. When i boot into safe mode, this doesn't happen, so I suspect it happens because of an app I installed, and now that I think about it while writing, I think it's probably Magisk Manager (I made it so that Magisk allows any superuser request, which is why I think Magisk has to do). I have the apps Phone Guardian (I always install it because I love it), Magisk Manager and the Official TWRP app.

Also something weird I noticed; Ever since the first time it bugged for me, whenever I boot into TWRP and then power off from the reboot menu, next boot is TWRP even if I don't do the button combo to boot into recovery (for my SM-T295 it's hold power + hold volume up at the same time when the device is off, then when it powers on, release all the keys and press power when promted to make the "bootloader unlocked" warning go away if necessary).

Does anyone have any ideas on why this is happening? Am I right on my guess that Magisk is faulty? Do I need to uninstall it and unroot if that's the case? Thank you all in advance.