I may have missed something in the above posts but as I’ve been on a sort of amatuerish journey with this recently – bear with me.
I did try to convert a 3x to a 2x with bash and ran into trouble with chainring bolts. I dont remember the exact details (I’d bought an SLX bashguard on here but the existing bolts wouldnt hold the chainring anymore) but charlie the bike monger sold me some bits which helped. Although I couldnt get it to work 100%.
The end-game is that after I destroyed an XT triple crank recently I’ve got an SLX 22-36 double chainset with a 34 cassette (ie a “proper” posh-like slx double/bash but for silly cheap euros).
This shifts with my existing 3x shifter / mech no problems. The bash seems to stop (so far) any dropped chains.
So there will probably be someone along shortly who can explain a simple cheap solution to the chainring bolts problem. It’s just not me!
On the other hand my 1×9 is easy! I dropped chains all the time til I fitted a superstar chainguide.
#Edit – forgot to say all I do is mince about in GT / Inners really. Proper mincing though!