I am a chozer Bitshuvah and have been regular to a lengthy morning seder of Shacharis. Now HaShem has blessed me with a family and because of the Korona virus I have started to work a job that requires me overnight sometimes up to a thirteen hour shift. When I get home in the morning I daven in Yechidous and without tefillin in fear that I sometimes fall asleep in the middle of Tefilah. What is the minimum requirement of Psukeh DeZimrah and is Tachanun , Ashrei to Aleinu necessary? Ain ke Alulanu and Kotores also necessary, especially if I might have already went over all the Korbonos on break at work?

Shalom, Thank you for your question. The minimum for davening shacharit (in times of need or exhaustion) is as follows:- hand washing, morning blessings, blessings of the Torah. In pesukah d’zimra, just Barouch She'Amar, Ashrei, Yishtabach. Everything from Barachu (which is not said without a minyan) until the end of the Amidah. Ahsrei and U’va LeTzion. Alainu, and Shir shel Yom. All the rest may be left out. Some of what we wrote may also be left out in times of greater need – but in your case I believe you should say what I have written here. You should try to have tefillin on for at least Shema. But if this is to hard, or you are very likely to fall asleep, as you wrote, you should put them on latter in the day (as soon as you can) and recite Shema with them on. Blessings.