I’ve heard many people say if one owns a dirah in Eertz Yisroel that one can keep 1 day Yom Tov. Is there a mekor for such a psak?
While I can’t vouch that there isn’t someone who might say this, however in a general context it is hard to believe. The idea is that the person be a “Ben Eretz Yisroel”, meaning that the person lives in Eretz Yisroel or at least visits. However just by buying an apartment in Eretz Yisroel doesn’t change one’s status regarding where the person lives. Additionally, the major contemporary poskim do not seem to make such a distinction, rather that it depends on the person’s overall life plans.