Did you put a battery charger on your battery and fully charge it. Use that multimeter and check the battery voltage, then put the red lead down on the starter stud, (car not running). The voltage at the stud should be the same as at the battery if its significantly less change the cable between the battery and the starter. Or clean up the connections.
There are also a bunch of grounds under the battery tray that should be cleaned up once in a while. You will have to remove the battery and battery tray to get to those.
I too noticed that your glow plug light does not come on. That is usually indicative of a 109 relay problem.
https://www.idparts.com/relay-109-a4b4a3-p-350.html
Change the relay it's up under the dash over your feet, right on top of that big 377 relay (wipers)making it hard to see. Yours is probably one of the old black models the new ones are grey.
I'm not sure the 109 is entirely your issue usually a failed 109 will allow the engine to crank until the battery goes dead it just won't allow the car to start.
I know you said you took a look at the fuses on top of the battery, however did you pull the little 10mm nuts off and clean up each connection? A friend of mine was having starting issues on his diesel bug and put in 3 different starters. He had "inspected" those fuses and they looked good, finally he took the first two apart and found a bit of corrosion under both, he cleaned them up and the car started fine.