For someone with your tastes I would suggest skipping The X-Files, at least at this stage of your life. It's a masterpiece much greater in many ways than countless acclaimed shows today- but it is very poor in terms of one area many people regard as supremely important- long term plotting. If you just want pure, no nonsense efficiency from plot and you can't (or don't feel you have time to) appreciate anything else such as very subtle character development or sophisticated classical cinematic qualities or the specific unique themes of each episode (which touch on real events and social issues, and range into subversive comedy, raw drama and brutal horror, as the show diversifies its stylistic template after season one), it just isn't for you. There is, of course, a recurring plot that you can watch all of without investing too much time, but that story, which started brilliantly (and remains that way mostly up until the Anasazi cliffhanger at the end of season two) eventually became bland, badly written, poorly handled over time (and bear in mind there are seven seasons of 20-24 episodes each after Anasazi), and is guaranteed to disappoint every viewer. Critics and fans agree almost all the best episodes are not related to that mythology plot.
Many viewers who have very limited time can benefit much more from watching a few selected standalone (monster of the week- MOTW) episodes. That is really the ideal fun, no-responsibility way to get into the series rather than starting at the beginning. Although I hesitate to recommend this for you, since you claim to only care about the overall plot (mythology) you also seem to be under the mistaken idea that The X-Files main focus artistically was on mythology serialization, so the rest is just filler. This is untrue. A lot of standalone episodes ARE filler but SO IS most of the mythology. The most innovative and influential episodes of the series are MOTW episodes- mostly ones that can be enjoyed with zero context- and mostly ones you have not seen yet, if you're only on season one.
Here is a list of some of the most universally beloved, award winning, essential standalone episodes. I have especially noted a few of the cream of the crop among these, with a *. If you have seen some or all these episodes (from a variety of seasons) and none of them particularly appealed to you, you have basically seen everything important about The X-Files and you can move on to other things and feel like you have a certainty it isn't for you. The heart of the series is the standalones.
Season 1: Squeeze* Ice Eve Beyond the Sea* Tooms Darkness Falls
Season 2: The Host* Sleepless Die Hand Die Verletzt Irresistible Humbug* Soft Light
Season 3: Clyde Bruckman's Final Repose War of the Coprophages* Pusher Jose Chung's From Outer Space* Quagmire Wetwired
Season 4: Home* Musings of a Cigarette Smoking Man Paper Hearts Never Again* Leonard Betts Small Potatoes
Season 5: Unusual Suspects The Post-Modern Prometheus* Kill Switch Bad Blood* Mind's Eye Folie a Deux
Season 6: Drive* Triangle How the Ghosts Stole Christmas Milagro The Unnatural Field Trip*
Season 7: X-Cops
And end there.