Gitflow and testing / deployment

I have a few questions around how do you handle testing and deployment when many developers are working on the same thing (that cant be split further) and you still want to deploy daily.

Currently we follow Gitflow where we have our features branches that everyone is working on an isolated feature. Features are merged into develop branch. Every now and then we take some time to cater for user requirements / bug fixes / quick features etc.

The end goal is to get those to PROD asap. My question is what process would you suggest such that:

1) We can deploy without introducing bureaucracy (e.g. Release on the last Friday of every month).

2) If someone commits code that is introducing a bug it doesn't affect someone else that has committed bugless code. In other words, if Coder A tries to fix a bug by introducing a new bug, and coder B has fixed his bug then coder's B code will get further into the pipeline while coder A will stay late fixing the bug :)

3) We cannot have unlimited testing environments. We also don't want to spend our day setting up testing environments. We need a solution that can work around this requirements (so test on feature branches is not an option unless I m missing something)

3) The testers know exactly without a doubt what they are approving to go into prod.

Btw we have a fairly extensive set of unit / functional tests but this question is about the process so those are not really relevant.

Also, I have researched all the other questions and nothing really addresses all of my questions. If you think there is one that does I would be happy to have a look.

Thanks