A common damage analysis method is to cut open the old oil filter and look for metal in the folds: grey metal - you probably have severe damage; no metal, good omen. Good luck!

There is a lot of stuff flying around here pulling the OP in lots of directions. I submit my 40 years in and around the automotive repair industry. I've built / repaired many engines over that time frame.

Synthetic oil helped keeping the motor from rapid damage.

1 1/2 QT in the pan is getting towards the bottom of the barrel so to speak but remember, the motor only ran a very short time at 1 1/2 qt because it was losing oil all along rather than being driven hundreds of miles at 1 1/2 qt. The low oil level is only an issue if the pickup becomes uncovered due to cornering / hills / rapid start stop.

Doing an oil analysis on the new oil is only partially valid as much of any "wear" elements left with the old oil. If you have the old oil, doing an analysis might be helpful however you won't get a 100 % valid test. for a valid test the engine must be run to stir up any contaminants and a sample taken from the middle of a drain rather than the start of the drain. ( This gives you an average not a gritty bottom test. )

Synthetic may have saved the turbo as well. I helped a guy fix a late 90's early 2000 VW turbo 4 cyl. He ran over something, broke the bottom of the aluminum oil pan out and lost all of the oil right now. He drove 2 or 3 miles at slow speeds then pulled over.

We pulled all the main and rod bearing caps, all looked in perfect condition, one main had started to transfer material from the bearing to the crank. We flaked the material off the crank polished it up and changed all rod and main bearings. Motor has been fine for a few years.

If you want to, pull the steel sump off ( easy ) and have a look at the bottom. If you don't see any metal flake at the bottom or in the 1 1/2 qt oil you had drained, nothing was damaged except the turbo wasn't done any favors and may or may not be OK.