Not at all!! Honestly it's pretty fast to load everything, stays connected, no lagging while browsing, watching vids, listening to music, etc. It's JUST streaming
Nature of WiFi and Internet
- historically, most internet traffic was download (consumptive)
- Streaming (or backing up) is Upload
Most home streaming (download) services have built-in buffers to hide WiFi and Internet latency/jitter issues [especially older WiFi which was more akin to a walkie-talkie .. with only 1 client able to talk at a time]
When live streaming, you don't have that luxury (for the most part, especially not with free services)
So if your WiFi is congested (or poorly functioning) is it entirely possible that it will seem ok for most consumptive traffic, just as it is likely that livestreaming is your only traffic type that is sensitive to sustained throughput.
So, yea, appearing ok without understanding the underlying technology, and having trouble with upload livestreaming, is completely within reason [not unusual]. And fixing such a connection issue for you would likely have NOTHING to do with OBS (though there are a couple of network related settings which might help ... or makes thing worse)
As for troubleshooting, there are really more involved methods/approaches, or test with a wired connection [ I don't believe comments like being unable to test a wired connection, unless someone is stealing service and trying to not get caught ... one can almost always move laptop to location with wired connection and use/borrow a laptop dock or USB-to-Ethernet adapter (US$10)].