Very hard to tell, we use both on different servers and TBH i did not feel any difference however if i have to give number i say 4 to nginx_apache and 5 out of 5 to openlitespeed
without knowing error log out put, it just shot in the dark
This might help
cd /usr/loca/directadmin/custombuild
./build update
./build rewrite_confs
this also help
https://forum.openlitespeed.org/threads/bug-update-openlitespeed-v1-7-1-to-openlitespeed-v1-7-2.4398/