1. what
@Harold said, so we can see your OBS settings
2. Your description is typical of a computer overwhelmed by what you've specifically asked it to do. Which leads to the important question - are your OBS settings unreasonable for your PC? is your PC simply not up to the task, regardless of settings? or do you need to optimize (or upgrade) your Operating system and/or computer setup?
*if* your OBS settings are 'wonky', then someone will hopefully spot that in your OBS log. You can also have an automated analyzer check your log... see my .sig for the link on this site
If you have background tasks consuming needed hardware resources (CPU, GPU, RAM, Disk I/O), your OBS log most likely won't show that. Doing some real-time hardware resource utilization monitoring in such a case may help identify one or more bottlenecks