Lots of options... what is your budget? feel free to look at my posts over recent months, as I've commented to a number of folks regarding House of Worship streaming. The system you need depends on how you are doing your streaming (there are more and less resource intensive approaches)... so it depends. With that said, I paid $1,500 for a upper-end business class PC, with Intel i7-10700k, 16GB RAM, GTX 1660 Super GPU, and 1TB HDD for storage, a 256GB SSD for OS, and that price included a premium support including next business day on-site service for 5 years. Could I have paid less (probably closer to $1K for just the PC)...sure .. but more involved than just the parts especially when dealing with non-technical volunteers. This PC should last for many years, and cover video editing as well. This PC is complete overkill today for OBS streaming with single USB webcam, and line-in mic from sound system. Very soon (ordering this week) we will add a NDI PTZ camera. If budget is tight, a used business class PC with a GTX GPU for $350-500 (3 yrs old?) should do fine. I avoid consumer grade equipment like the plague, so I won't comment about what in that range might work.
As others read on this forum, a 5 year old gaming laptop with an i5-6500 wasn't enough for what we do (including non-optimized OBS.. 'cuz I don't know enough)
Hopefully that gives you a range to consider. For video encoding support, and a decent lifespan, I'd recommend a GTX 1650 Super GPU (I got next step up in GPU only because vendor didn't have the PC I wanted with the 1650S). I don't have specifics, but others will tell you for now, best to avoid AMD GPU due to lack of x.264 encoding support (ie offload task from GPU)
If you have more specific questions, feel free to ask