Financing really is the wildcard. USDA loans offer extremely low interest rates, but they can extend the closing date for some time due to their more strict home requirements and staff shortage.
NIFA/FHA also seems to occasionally take longer, followed by NIFA/CONVENTIONAL, Conventional, then cash.
A lot of it comes down to your lender, and how the lender, Realtor, and title company all communicate. Your Realtor should be the one advocating for you and your timeline whether you need to close on your home in 2 weeks or your lender won't return your phone calls. No matter what the case, if you let your Realtor know what your needs are and when those needs are to be met, any good agent should make every effort to accommodate you as their client.