BLU C5L --Oreo 8.1.0GO edition(2019)

Registration date
Wednesday March 25, 2015
Last seen
December 6, 2021
Got this BLU C5L w/ Oreo 8.1.0GO edition. Phones been displaying undesirable behavior and believe I need to re-flash ROM. I've spent numerous hours trying to find the exact, original ROM. And, even found 2 versions of what could be the "original"(??) [mediatek & spreadtrum....and this phone has both] So, asking for some help. Anyone know where I can D/l the "exact original" ROM for this phone?And, would re-flashing recover about 2.6Gb in missing data storage? In other words, this phone only has 5.2Gb (total) available, after O.S. and other essentials it allows for just under 3Gb. There are other issues (quite a few) and what I want is for this phone to perform as it did originally. Somebody with knowledge/experience of this particular model would be appreciated. Oh, BTW, Blu "support" was a damn joke!!! THANX