Some people want to modify the 1st or 2nd or 4th, etc.
Do you think that doing so would make all the others vulnerable to attack?
Some higher-numbered amendments have already been repealed, of course, so there’s noting sacred about those past the first ten.
If by modifying you mean through a Constitutional amendment, then no, modifying (or even repealing) one would have no effect on the others.
That problem comes into play when people (and judges) decide to “interpret” the meaning of those amendments and thereby modify their meaning. If this is allowed then yes, the protections afforded by all are in danger. Once we decide that any one of the amendments in the Bill of Rights does not apply to the individual then it is a simple, logical step to say that none of them do.