I started on a 29er Hard Tail with a 3x9 set up,,stripped it to a 1x9 pretty quick,, running a 32 ring up front and a 12x36 cassette.
Them big heavy 29er hoops,,,I just did not have the engines for that set up but I hated front derailleur's and all that noise..
sold it.
I move to a 25.5" wheeled full suspension,,wow,,now I could accelerate big time !!!
It started with a much better 3x9 SLX system,, and,, you guessed it ! stripped off all the front junk and for three months ran a 32 ring out front and a 11x34 cassette out back,,

Then came just what I needed,, the Newly updated Shimano Deore XT M 8000
I am now Running a Race Face Narrow wide 32 tooth chain ring up front,
(NO chain guard/keeper and I never drop a chain),,
and the 12X42 toothed 11 speed cassette out back,, Very affordable
shifter $75
Cassette $130
Derailleur $120, with the new user externally adjustable clutch !
Chain Is some new fancy super slick refuses to pick up dirt Shimano chain for $40..

Shifts perfect, I'm told It shifts just like the now over priced Sram X01 stuff,,you know,, the system with the
$350 Cassette,
the $350 Derailleur,,and so on,,,,

1x9's repeat so many gears so 27 is really what,,15 ?
2x10's are still noisy and still have some repeats right ?

Cleaned up my handle bars, dropped a pound of junk off the bike by loosing the front gear system,,,, Just sayin..