You can try my plug-in:
https://forum.audacityteam.org/t/arrange-your-tracks-with-chain-it-up-ny/26201/1
The first track must be at the top.
It is probably best to align only two tracks in one step, depending on the length of the cd tracks. the durations should in any case not exceed a half hour.
After finishing a pair, render them (Ctrl-m on my machine).
select the next couple of pairs and proceed again.
Audio books are very long, thus if you’ve created chunks of two hours or so, it may be necessary to align them manually in the last step.
That’s because Nyquist calculates all sounds in memory and 13 hours are the absolute maximum for a sound (only to be kept in memory, no calculation done yet). Thus, save always, when a step has been completed successfully.
There are external programs that may do a better job, sox for example. However, it works via the command line and that can be complicated at times.
good luck