On paper I have 1 gig internet and this was certainly true before the pandemic, but now my apartment's fiber is clearly having issues with the whole complex being home and using the Internet at the same time.
The challenge is some of thr broadband networks aren't being transparent about it. They won't admit to it, etc. Luckily I've found folks in a few companies who are willing to go off the record and explain what is the state of the last mile and give dates around planned upgrades (which are impacted due to permitting delays due to city employees struggling with covid restrictions).
I highly recommend getting two ISPs at home (cable + DSL/fttx/etc.) if you can.
As for Corp networks...they should be doing more with providing their employees some tooling to indicate if the issue is their ISP or the Corp network. It's a sad state that VPN appliances cost as much as they do (surprise - you could probably build a cheaper/better one but something something no one ever got fired for buying Cisco/etc).
You can totally buy guaranteed connectivity ... buy you will dislike the price tag.
Although my hunch is that you probably have oversaturation of wifi channels if you are in apartment building or something like that. Since everything is streaming wireless nowadays.
Guaranteed bandwidth to internet is nonsensical concept because there is no single internet to have the bandwidth to.
Guaranteed bandwidth to some specific network or host, that is valid concept, but it is very different thing and usually you can't get such thing to any arbitrary network.
As a residential subscriber in a US apartment building I really don't think I can actually purchase guaranteed 1 gig from any ISP.
This totally seems to be the case. I've had way more problems to the connection from home being slow then I've had because of the corporate network. This also seems to be true for everyone that I've worked with. At this point I don't think there would be much benefit to upgrading the corporate network it's just not where the bottleneck is.