Obs can also be used for camera use.

It's easy enough to record using Zoom. Start a meeting with only yourself. I've used OBS too and it's fine, but not necessary if you're just looking to record something simple.

You'll almost certainly want something to edit the videos. Rather than trying for a perfect take, if i flubbed something I would start over from a convenient place and edit out the bad part. I hated Adobe Premiere. Reaper isn't really ideal for this stuff, but at least it isn't Premiere. I dont remember if OBS had anything. LightWorks was OK.

You'll want a good mic. Although lapel mics are ideal for your use, Bluetooth tends to suck. This webcam has an OK mic. https://www.logitech.com/en-us/products/webcams/c920s-pro-hd-webcam.960-001257.html

For unrelated reasons, I had an audio interface (Scarlett 4i4) and a cardiod mic (MXL 770). The Scarlett is very nice. I don't love the 770, but it's better tham a webcam. These are not critical but if you plan to do this a lot, these would make it sound noticably better, and maybe someone has a better mic recommendation, and again lapel would be perfect for lectures. Somewhere I got a baffle like this for $20 to $30. https://www.bhphotovideo.com/c/product/1116780-REG/primacoustic_p300_0101_voxguard_vu_vocal.html

It makes a difference and for a low price it's nice to have if you aren't using a lapel mic. I wouldn't pay $100 for one.