I have what I believe to be big issues. I took my car in to get the timing cover replaced do to a leak, after replacing it ran totally fine for about 80miles. I did a pull and the timing pulley came loose and both belts snapped. After tightening it back down and starting the car back up it was shaking and sounded like it was running on 6 cylinders I got codes for cylinder 2,3 and 7 (misfire cylinder damage) on each cylinder. Did a compression test and it was low on those cylinders. Car runs on 5 cylinders no white smoke coming out please help!

I would try to get a bore scope, pull those plugs again and look inside and see if there is valve damage - confirm compression numbers , also did you mean crank pulley came loose/off / - if so the key way on the crank and pulley may be damaged... sounds like you may have to pull your heads. Not good - sorry

Not many mechanics are qualified to mess with the crank pulley. It requires special tools and some nerve to tighten and a new bolt. The biggest “while your in there item” is to replace is the oil pump chain tensioner.