Is it permissible for my son, who resides in Saudi Arabia, to perform Hajj on my behalf this year, given that I am 65 years old and live in Egypt, and that Hajj this year is restricted to residents of Saudi Arabia?

You are not permitted to appoint someone to perform Hajj on your behalf for the obligatory Hajj (Hajjat al-Islam) merely because Hajj is prohibited this year, as this prohibition is temporary. The incapacitation that permits deputization is that which is not expected to cease. If you are financially and physically capable, and your inability to perform Hajj is temporary, then deputization is not permissible. Rather, you must perform Hajj yourself when the impediment is removed. If you are not obligated to perform Hajj this year due to the impediment, and you die, you will not be questioned about it, and you are not required to deputize someone under the pretext of not guaranteeing your survival; for the Sacred Law did not prescribe that.