I think you are misunderstanding some parameters. The service ceiling of the aircraft is 20,700 meters, lets round that to 68,000 feet. Additionally, the max speed without damage is Mach 2.8, though it can exceed that and irreparably damage the engines if really pushed. Ive had this model meet those parameters in msfs2020.
The max altitude record was with a modified aircraft that basically zoom climbed and stalled out. I’m betting it can be done in the sim too but I haven’t tried. The max altitude was not for sustained flight.
Agreed sounds could be better but I suspect they are not sound experts. Note that the sounds are not purely F-18 but a mix incorporating F-18 with custom afterburner sounds plus cockpit sounds.