Interesting question, Rachael, @Libitina ,
Up front, I declare personal interest in Faith guitars, owning an (OM) Earth which consists a Fishman Flex Blend pick-up/ pre-amp system (a bridge plate mounted body pickup & condenser mic). As an aside, I was quite shocked at price increases since 2020 !
Mics ābetterā than plug-in ? Imo, itās āhorses for coursesā, and entirely dependent upon what you hope to achieve in terms of output. There are so many variables: performance space, signal chain, guitar, mic(s), pickups, instrumental play and/or singing too, ā¦ the list goes on.
Cost is also a factor given one can spend many (many) more ābucksā on a mic set-up than the acoustic guitar. Many pro singer/song-writers use both condenser mic and body pick-up mixed together when performing live.
Pickup devices all have their own fan-club, although most devices these days are fairly effective and generally compliment the guitar to which they are fitted. Obviously retro-fitting is yet another ārabbit holeā.
You touched upon guitar size: I have found thereās no substitute to trying out many options. From experience I do not pay much attention to actual spec measurements, and the best advice I have been given on this is to take along your current guitar and use it as a baseline as you try out different makes and styles.
A parting thought on acoustic guitars: perhaps consider a 12-fret as a potential option. The shorter neck can change the whole dynamic in terms of comfort and playing posture.
I hope this is of some help.