بسم الله الرحمن الرحيم
Hajj-e-Tamattu or Hajj-e-Qiran are performed with Umrah, so if you find Hajj-e-Tamattu or Hajj-e-Qiran hard due to shortage of time and crowd then you should perform Hajj-e-Ifrad; there is no sin in it according to Shariah.
Allah knows Best!
Darul Uloom Deoband
This answer was collected from the official ifta website of Darul Uloom Deoband in India.