Pretty much. Landing sites are rather self-evident I'm afraid and thus easily covered. So you'll need to prep the area before you even
think about landing troops.
Then there is the fact that amphib vehicles are, by their very nature, going to be weaker than their non-amphib counterparts. To get that capability, you have to sacrifice quite a bit to get it to work right, things like firepower (less powerful weapon, less ammo, or in rare cases even
both) and armor. Even military officers of the past concluded that the best possible place to
stop an amphibious assault is at the beach and nowhere else. With ASMs making it harder for Amphib ships to properly set up units for the assault and give them the proper support, better and better heavy weapons (especially artillery and ATGMs) capable of harming said amphibs, and other factors when fighting a
semi-competent opponent... you'll get tremendous casualties if not outright destruction of your units due to the inevitable counterattack with everything short of the NBC kitchen sink at the minimum.
That isn't including the fact that Sensor Fusion is likely to proliferate, meaning that you'll have a situation where the sensor density is so dense that it would be
very obvious when it comes to jamming and electronic countermeasures, meaning that you'll have to have everything amphib and amphib related
equipped with stealth which has its own set of problems (the reason that the USN hasn't gotten anything stealth-related?
Seawater corrodes every RAM coating before the F-35s into uselessness, seriously, seawater is some scary-ass shit in the corrosion department). ... and before you say that being low to the sea level would protect you, the same radar tech that is designed to find submarine periscopes can be easily used to find high-draft amphibs (which has its own set of problems).