YES most trailer tires are rated for 65mph max. Some have 75 mph rating. You can check what your tires are rated for......look on sidewall for info.
I don't care IF posted speed limit is 75 mph (or 80).......that is the MAX Speed LIMIT. Minimum on most Interstates is 45 mph.
My trailer tires are rated for 75 mph BUT I tow at 62-65 mph when using an Interstate. And others can use the left lane(s) and pass me ALL day long.
I'm not out there to speed along towing 14K (22k Combined), getting worst mpg, turning trip into a white knuckler just because.......(I got over that after high school).
I do not change the setting on my brake controller. It is setup to stop trailer, activates in conjunction with truck braking so that they stop as a combo.
Don't know what truck you have.....what engine braking or tranny set up.
I have an exhaust brake that is used on all downhill grades PLUS tranny downshifts on deceleration/braking in Tow/Haul Mode.
And if I need to slow I 'stab' brakes firmly to scrub off 10 mph and then get off brakes so they don't overheat.
If I find I have to do that frequently then I downshift.