I did the same thing, as a side project when covid first hit. It's a fun and difficult problem to solve efficiently. I remember seeing some videos on YouTube of algorithms that could do it as well.
nice, what did you end up going with? I built a "scoring" function for candidates based on how many other words can intersect each letter (based on grid layout and squares already filled) plus a backtracking system. ended up working pretty well, although each grid took >1 minute. I used an NYT historical word list as the dictionary
interesting - I was trying to think of a backtracking system as well, but wasn't able to create something efficient. Did it work well for large dense crosswords?
I had good success using a DAWG for pruning, and letter-wise (rather than word-wise) branching, picking the letter with fewest options. If you want to get fancy, you can use back-jumping instead of backtracking.