Shalom u’vracha,
According to the view of Maran Rabbi Ovadia Yosef zt”l, a young man from outside Israel who is independent and is not supported at his parents’ table, and who is in Israel on Yom Tov, does not need to observe the second day of Yom Tov of the Diaspora—even if he intends to return abroad after the festival—provided that, should he be offered a suitable shidduch from Israel, he would establish his residence in Israel.
Even a young man who is supported at his parents’ table and is not independent does not need to observe the second day of Yom Tov of the Diaspora if, should he find a shidduch from Israel, his parents would not object to his remaining in Israel and establishing his home there. This is because the second day of Yom Tov is only a minhag, and it is easy to find grounds to define him as belonging to Israel.
Only a young man who is supported at his parents’ table, whose parents object to his remaining in Israel and establishing a home there, and who heeds them in this regard, must observe the second day of Yom Tov of the Diaspora while he is in Israel.
Therefore, you should assess your own personal circumstances: whether, from your perspective, there is an option that you would remain in Israel if you were offered a suitable and good shidduch there. If the answer is affirmative, then according to Maran Rabbi Ovadia Yosef zt”l, you do not need to observe the second day of Yom Tov of the Diaspora.
It is important to note that according to Ashkenazic practice, as long as the young man presently intends to return abroad, he must observe two days of Yom Tov of the Diaspora in all cases.
With blessings,
Rabbi David Ohayon
Jerusalem