2000 Isuzu rodeo with pronounced engine noise

I just recently acquired a 2000 Isuzu rodeo. The last owner said their girlfriend drove it with low oil, and it damaged the engine. On starting the car, there is a somewhat loud clicking/tapping noise from the engine. It speeds up if you step on the gas, and seemed to be louder with the camshaft cover off. I believe it to be an issue with a vlave or cam or some other part in the head, but the person I am working ont his car with thinks the problem lies in the lower end, and wants to rebuild that. We are stumped, so if anyone can help, it would be nice to avoid a rebuild.

Top end/head noises tend to be - well, up top, and sound more like tick-tick-tick or tap-tap-tap.

Block noises tend to be down lower and also tend to sound lower - knock-knock or thunk-thunk.

You called it clicking/tapping. I’d guess that’s up top.

I’m not sure it matters. Its too late to avoid the need for a rebuild. That need arose as soon as it was driven while low on oil.