aubrey.
i KNOW some (many ? lol.) will disagree with the following.
but what the hey here goes.
ive used biab for quite some time over many many years.
thus i know its many foibles. ive done a slew of songs useing it.
1. i use biab for bed traks initially laying down the song.
ie like an architect building the plans for a house.
i dont use fancy guitar plug ins initially. like amplitube.
or guitar rig or whatever is in vogue.
in fact i use no heavy duty plug ins initially while i'm laying out a song. even if the style has such.
i focus on a strong rhythm section.
one needs to build a good house foundation, before one focuses on all the pretty things on the outside of the house imho. to quote an old pro producer whose wisdom i once had the benefit of years ago. a real carmudgeon lol.
2. then i transfer the biab bed traks to a daw multitrack software.
3. after ive done all my guide vocs and the rest of the traks in the daw software.
(eg reaper/RB/whatever.) THEN
4. i go back to biab as a seperate project file with same chord structure of course, and then think about guitar lead breaks.ie the "fancy stuff on the house"
once i'm happy i then move those to the daw and possibly reinforce with my own guitar parts etc etc.
I ONLY EVER USE GUITAR PLUG INS in the daw multitrack
software, never in biab.

my opinion is, some guitar plug ins can be rather heavy on computer resources.
and as youve found out rendering time. no probs if one has a beast of a pc , but most people dont have such.

ive found my song creation life is easier this way.
in summary i dont use fancy plug ins, in biab , i use them in the daw software.
just a suggestion.
(ymmv)
merry xmas.
muso.

my songs....mixed for good earbuds...(fyi..my vocs on all songs..)
https://soundcloud.com/alfsongs
(90 songs created useing bb/rb)
(lots of tips of mine in pg tips forum.)