If the actual mitzvah couldn't be fulfilled properly, then it would be suspended. The difficulty in this case is that it is not residence in Eretz Yisrael itself that was difficult to fulfill properly, but other mitzvahs that would follow once a person resides in EY.
Nonetheless, if Rabbeinu Chaim Cohen considered the mitzvahs dependent on the Land to be almost impossible to fulfill (in his time), that would legitimize a ruling that one should avoid fulfilling the mitzvah of residing in EY. It's also possible that Rabbeinu Chaim Cohen doesn't consider residence in EY an absolute mitzvah, unlike Ramban, or that he considers it to be a mitzvah incumbent on the public and dependent on the spiritual degree of the public, and specifically whether they can live up to the mitzvahs associated with it and linked to it.
Are there are other Mitzvos asei thst are suspended because it would be difficult to fulfill them properly?
If the actual mitzvah couldn't be fulfilled properly, then it would be suspended. The difficulty in this case is that it is not residence in Eretz Yisrael itself that was difficult to fulfill properly, but other mitzvahs that would follow once a person resides in EY.
Nonetheless, if Rabbeinu Chaim Cohen considered the mitzvahs dependent on the Land to be almost impossible to fulfill (in his time), that would legitimize a ruling that one should avoid fulfilling the mitzvah of residing in EY. It's also possible that Rabbeinu Chaim Cohen doesn't consider residence in EY an absolute mitzvah, unlike Ramban, or that he considers it to be a mitzvah incumbent on the public and dependent on the spiritual degree of the public, and specifically whether they can live up to the mitzvahs associated with it and linked to it.