Running the bots db modification requires starting eqemu_update.pl manually and selecting option 4 (it can be done from world if there is a
standard database update that triggers the options menu.)
If you've already done this step, it should not need to be performed again.
For the 'enabling' of bots in the server code, you will need to re-run cmake, select the 'bots' checkbox, then configure and generate the new solution files.
Afterwards, you will have to compile the server code again so that the bot code can be integrated into a newly compiled binary (executable.)
If you have done this already, it does not have to be done again (at least until the server code is updated.)
The eqemu_update.pl script shouldn't allow access to option 4 unless there is a 'bots-enabled' binary in your server folder.
You're not confusing bots with mercs, are you?
They are not the same and are not accessed through vendors like mercs are.
Try typing this command in-game to see what is returned: