Suggested

headquarters upgrade

I think I’m the next update you should be able to upgrade more than 1 item in the headquarter section at a time instead of having to wait 5 days between builds or wasting coins having to quick build everything 

I think the 1 building at a time thing helps in maintaining the realism and competition. It seems realistic that only one particular building at a time can be renovated and the competition also doesn't die down as the big teams can't develop all the headquarters at once (while the newer teams have more and more work to do). It's a time taking process, sure, but it's just another aspect of building your team from the scratch

Jsghccc

I think it should be 2 at a time with most buildings taking 5 days to build or 1 at a time but reduce the time it takes to build.

Don’t really agree with having to use coins to quick build stuff obviously just a money making thing to get people to buy coins from the shop 

Most?  Design and Technology each take 5 days, Youth Academy takes 3, with Manufacturing, O&A, and Simulator each need 2.

I think it's fine as it is, a lot of this game is about having patience