real-time video encoding is VERY computationally demanding. So, if you go for lower-end system, expect to spend time at optimizing both OS and OBS for an under-powered PC. That also means less flexibility/complexity/sophistication on your OBS setup... which may be fine.. just be aware of the limitations such a system would impose
I'd recommend becoming adept at how to monitor hardware resource (CPU, GPU, RAM, etc) utilization [for ex. using Task manager’s Performance tab and/or Resource Monitor] for bottlenecks
That said, an i5-9400T is on the lower end, and a low power version at that, and being 2 generations old at this point, for barely any more money you could get a similar generation i7 though none have of them have hyper-threading..
And consider what you plan to do, like noise filters/effects, streaming resolution, whether you'll be using a resource intensive browser like Chrome to monitor live stream provider (always desired, but if on same PC, you need to account for associated resource consumption)
Assuming typical church volunteer pool of resources, and wanting a system you can buy now, and use for 3+ years, I'd recommend getting a lower-end gaming system with a 10th gen i7, 16GB RAM, SSD, and a GTX 1650 Super (w/ Turing NVENC) or better GPU. Personally I avoid consumer grade PCs (going for business class instead due to support and longevity) but on a tight budget, you should be able to get a 6core/12-thread CPU and GTX1650S for somewhere in the $500-700 range, and less if used. And such a system should have years of life if properly maintained (connected to an auto-voltage regulating (AVR) power supply/UPS). If that is too much money, a prior gen GTX GPU like the 1050Ti will provide lower vide quality but may suffice for your needs ?? other can better describe differences between older NVENC and Turing/Ampere based NVENC, I've only read other's comments
Can an lower end system work? absolutely. but I'd recommend you consider how much time and expertise you/your team has to optimize a setup, vs getting a slightly overkill system, and having the headroom to make mistakes in the beginning and still have a reliable stream. For us, it was more important to have a good Sunday service stream, than try to save a couple of hundred dollars on initial purchase. And the PC is only one piece of the overall House of Worship live stream setup.. with camera, audio, network, and possibly lighting all coming into play
Good luck
