Wel, as I said, “neise sefer venichzeh”- let us look at the sources. “vochindik’ brought down a number of sources to bolster his view about the “issur’ of conquering eretz Yisroel.Well, I have looked at one of these sources (haven’t had time yet to look at others) and this is the ‘megilas esther’ on the Ramban in sefer hamitzvos. ‘vochindik” didn’t give us the exact place so let me do it; it is in the part where the Ramban adds mitzvot that the Rambam did not quote and it is mitzvah 4- (in the Ramban’s count) and the megilas esther. What ‘vochindik’ conveniently ommitted is the Ramban himself- who clearly says that, even in our times, it is a mitzvah to settle Israel (Yishuv ho-oretz) and to take it from the gentiles. See the whole section.
On this- the “megilas esther” tries to explain why the Rambam did not count this as a mitzvah and, in his eyes, it is only “bizman hamikdosh” and “bijemos hamoshiach”. He does mention the gemoro in kesubos as a source. SO- the Rambam is silent on this, the Ramban is enthusiastic about this and ignores the gemoro in kesubos and the megilas esther -trying to understand the rambam- decides that it is not a mitzvah today. At best, we have a machlokes and the Ramban is good enough for me as a source.I’ll
try to research the other sources.