BLU C5L-Oreo 8.1.0 GO edition

I have this BLU C5L-Oreo GO edition that has a number of operation issues. I'd like to re-flash the ROM and in trying to do so, have encountered a number of problems. Let's start with this; I'm trying to find the "original" ROM for this phone (Oreo 8.1.0 GO /2019). Have been to a multitude of sites searching for this ROM. Can't believe it's been so difficult to find. Been to BLU support (what a waste of time), been through literally dozens of sites searching for this ROM and have come up empty. I've been told it has to be the ROM that, specifically, was designed for this particular phone/model/year as other ROM's (upgrades, customs and after market) do not perform well. Could you direct me to THE site that would have this specific ROM?
THANKS