What are you drilling all these holes for now? 24 anchors sounds like a decent sized project. And a hammer drill for 3/8" holes in concrete sounds crazy. Maybe for old clay brick, but if this is good concrete you are going to have a tough time.

I honestly don't understand not wanting to buy a proper tool. It will make this job seriously 1000x easier than a hammer drill, and you'll have it for next time. Also, if you get a rotary hammer with a switch to put it in hammer only mode you can use it with a chisel for demo work. You'll never know when it will come in handy. Don’t be a cheepskate, it’s definitely a sign of being an amateur.

Most of my vast tool collection was purchased and paid for by the immediate job at hand, and after about 15 years I have pretty much have a few of everything.

I'm not trying to insult you at all here, it's just that you came asking for advice, and the only thing you seem sure of, that you will never have to do this again, seems particularly short sighted to anyone with experience.

https://a.co/d/cI8aD2d Here is an absolute piece of cheap Chinese junk for $89, but honestly it will do better for OP than ANY hammer drill.

I recommend sticking with a brand name if you are a pro, but I've had decent luck with several of these cheap Chinese tools I've picked up for my guys in a pinch cause I already have plenty of Makita and Hitachi rotary and demolition hammers.