I'm sorry about your setback first of all.
Doing "a bit of everything" is probably good from the injury-prevention standpoint. I am afraid of getting an injury that would wreck my cardio workouts a.k.a. the only reason my left lung does not feel like a bowl of soup. But I hear you on wanting a plan of action for maximal mucus clearance and FEV1 boost.
So, I should preface this by saying my FEV1 has not actually improved since starting to work out regularly. But everything else has: amount of trapped mucus, exacerbation rate, resting heart rate, cholesterol level, belly from having three kids, and I've increased my because of more muscle and fewer exacerbations.
Here's my "plan"
I belong to a gym that costs $70 a month--I live in the NY metro area and this is on the lower end of cost. Doing a la carte classes around town would be $15-20 each. Either way, my gym membership is deducted from my family's flexible spending account because my pulmo wrote a note about bronchiectasis, mucus clearance and exercise.
I go to two hour-long Zumba dance classes a week (used to be 3+ but I substituted in 1-2 hours of rock climbing). These classes are FUN. I look forward to the music, perfecting the moves, saying hi to the regulars. (And the regulars range in age, size, and gender, which is cool.)
I love to check out different teachers' styles. Some are very Bollywood/Bhangra focused; others are Latin focused and my favorite, I think, are the Hip-Hop focused ones. I have to work extra hard to make my skinny butt move. Some teachers get my heartrate into the 140s. My favorite teacher, no joke, gets my heartrate into the 170s for a big chunk of the class. Everyone has different target heart rates, so I only compare me with me. When I push past 180, I feel queasy and surreal, so that's my no-go zone.
For me, dance works, both mentally and physically. Other sports feel like an obligation, well, except rock climbing and maybe team sports. If I couldn't dance, I think I'd try an adult soccer league. But that might be seasonal, which a gym membership is not. (And I'd need a huge review of ball skills.)
So, that's my pitch for Zumba...in a gym that offers it at least 3x a week with talented instructors. Even a slower class "Zumba Gold" which is geared toward seniors can be engaging if the instructor is skilled. Setting aerobics moves like the "grapevine" to Salsa music does not cut it IMHO.
I'll be curious to hear what works for you. A lot of people here swear by jogging. That said, it was Nightwriter on this board who convinced me to try Zumba. (Thank you again, Nightwriter, if you're reading.)
BTW, I had some probably-flu/viral thing this spring too and it left me extra congested/inflamed for months. I wonder if it was a bad strain of something...