It might not solve the entire issue, but I submitted a support ticket weeks ago about the long start-up times for a V4 cloud, specifically around checking pre-requisites. I have been informed that there have been some improvements made that will be released in version 7.4. This should happen at the end of this month.
Is it possible to do a simple benchmark for application performance as well? The longer startup time makes me assume that the v4 environment you're using is just a lot slower as a whole than your v3 environment.
Can you let me know which Mendix version you are using for this? If it's a fairly recent one it will be a bit slower for a couple of weeks, until we include that version in the pre-loaded runtime list in v4.
I have a Mendix 7.4 application in the V4 cloud and it feels rather slow to me. Any updates on performance regarding V4 cloud?
Edit: i timed it transfer 49 seconds starting 77 seconds so its not as bad as i thought. Sure felt a lot longer yesterday. (My app is really small)