Metrobus is even more unpredictable than Metrorail because buses get stuck in traffic. Use your smartphone to figure out where the next bus is, because the bus schedule is essentially fiction.
Major suggestion is don’t worry so much, it’s a train trip to get you where you need to be, relax about it, it’s relatively safe and reliable and pretty much set up for you to succeed in your goal of arriving at your desired destination, in that respect it’s working for you.
Reading the responses inspired me to go look up slugging in DC. Pretty impressive community problem solving 
True - but these are not, normally, daily occurrences. So on average, your Metro commute will be a bit more reliable than a driving commute (I used to work 9 miles from home, and the commute ranged anywhere from 25 minutes to an hour depending on traffic and weather).
The trains can be a godawful zoo in the afternoons especially. The orange line seemed to be especially awful. Back when I worked downtown, I would occasionally get on it in the wrong direction for a couple of stops, just so I had a better chance of getting on at all, and maybe even getting a seat.
Sounds like the OP won’t be hitting the truly horrible stations like Farragut West (phew!).
One real annoyance is the escalators, which are in a constant state of broke. The Washington Post ran a funny article comparing DC metro escalators to Moscow metro escalators, which never break despite being longer, older, more crowded, and in freaking Russia; a country not know for efficiency or incorruptability.
Well, to be fair, the Moscow Metro apparently has an escalator repair staff of 3,000, while the DC Metro has what seems to be a staff of about 3.
Yes, there’s an old joke that goes something like this:
“It was really cold in DC yesterday. So cold, in fact, that the escalators on Metro were frozen in place!”
There were slugs around Crystal City as well when I worked there a couple of years ago.