Does your internet Throttle during Peak Period.
I dunno what wrong, but my internet tend to stop and start or become very slow for a few seconds then recover immediately. I rebooted very equipment I have, and some games is really affected.
This usually happen during peak hours.
Don't confuse congestion with throttling...
You don't have a dedicated 1gbps connection at home, you have a "best effort" 1gbps connection which is shared with other users in several places. A dedicated 1gbps would cost a LOT more.
Wireless - the wireless spectrum is shared by everyone within range and beyond - even users that are out of range while their networks won't be strong enough for you to connect and use, their traffic will still generate noise which interferes with your usage... Also devices using older wireless standards will hog more of the spectrum than newer standards.
GPON - home fibre uses GPON which allows for up to 128 users to share a single port.
Upstream - the connections from your ISP to the rest of the internet is shared between all users of the ISP... Most ISPs will have multiple links of varying capacity to different places, any of those links could become saturated.
Target servers - whatever you're connecting to is also shared amongst everyone accessing the same service.
It's quite normal that things would slow down at peak times, this is how they meet the price point of the service, and the limitations of wifi are unavoidable laws of physics.