I think you can remove the inner crank gear, the FD, & front shifter assembly with associated cabling to achieve the "cleaner" look you are after.
Not sure which combo of parts all would jive, but adding to the parts cart, I think you'll need to invest in a rear shifter assembly. In short, a RD, 11sp cassette, chain, new rear shifter assembly, & you minds well restring in a new cable with new cable housing too. I wouldn't expect you'd need to swap the caliber, but someone with more knowledge will need to confirm that detail.