I would generally agree with you, but in this case, Verizon has already been subject to such a rule for over a decade as a condition of the 700MHz spectrum. Verizon does offer subsidized/financed devices like the other carriers, it just doesn’t SIM lock them beyond the initial period.
Given this data point, I think it’s a good idea to expand to the other carriers.
Who’s your ISP? I’d suspect it’s the ISP treating tethering traffic differently. I notice that on my phone (AT&T postpaid), my phone and tethered computer even get different IPv4 addresses. I’m not saying performance should be identical if they are sharing an IPv4 address, moreso just showing that ISPs can handle tethering traffic differently.
EDIT: just saw you’re on Orange, oops! I don’t know how they operate, they could be handling tethering traffic differently from native mobile.
Btw, you can keep circle to search on and use GoodLock to remove the nav bar. You just press and hold in the middle where the nav bar would be to activate circle to search