you should be changing it every 3k miles in my opinion, especially if you're trying to keep it a clean engine with no buildup. personally I would run BG EPR cleaner with MOA, or there's other oil additive cleaners out there as well if you want something cheaper. I don't know if this will change the oil consumption, but if you go into it with the mindset of - oh I just want to give my engine a spa cleaning - then it's worth a shot right? about 30$ for the BG EPR and MOA ( cleaner and protective additive that goes in the new oil - don't do the cleaner until you are ready to do an oil change ).
when you say you don't see any external leaks - did you check the mentioned areas? valve covers, oil filter housing, oil pan, timing cover?
2QTs is definitely outside of normal, i'm just a DIY'er so take my advice with a grain of salt, just been doing my own car work since 2017. if it was me, cause I don't like to run straight to shops, i'd do the cleaning, maybe switch it up to 5W-30 ( I started using that since my timing job ) and monitor it during this next oil interval before calling shops around.