I would have thought with the cello you wouldn't need to be concerned about the tenor clef-only the bass.
Well, the cello has a pretty big range. The upper-most notes would be 15 lines above the bass clef. I wouldn't let this stop me from learning as those notes aren't used very often for non-solo purposes.
I watched a couple of YouTube symphonies last night and wondered how the musicians knew when to start and when to stop or how soft to play.
In addition to pitch and duration to hold a given note, there are rests written and dynamic references. It sounds much more complicated than it really is. You learn the clef, you learn what the key signature means, you learn how to read and count time signatures and based on that, how long each notated note is held. You learn incidental notes.
Learning the basics of reading music is less complex than diagraming sentences. I think a lot of people that have learned a given instrument without knowing how to read music develop an aversion to learning to read. Guitar, bass and keyboards the context of rock, pop and country definitely don't require much knowledge of written music. If you want to learn most any other instrument with an interest in most musics written before 1930 or so, being able to read music is absolutely invaluable.
Everyone in the orchestra was reading music but the one doing the violin concerto. I've never seen a concerto where the main violin/cello musician read music. I found that rather odd.
With music that involved, it's somewhat understood that the featured musician knows the music forwards, backwards and can start any section at any moment. Most touring professional musicians have likely known the major concerti for their instruments for many years. Nobody can sight read music that complex.
I'm not trying to talk anyone into anything, but it's simply not nearly as complicated as many people think it is. Like I said, there are hundreds of thousands of kids as young as five or six years old that learn to read music every year and less than two or three percent of them are genius-level players. I'd say one can get the basics in a week or so and then learn the additional stuff as the complexity of the music requires. If you're just starting out on the instrument, you will have a long time to learn the more challenging stuff. For the first few weeks, you'll be playing open strings (four notes) and learning where to put your fingers while staying in one or two key signatures.