FYI - this is primarily a user forum, and while it is monitored by the software developers, they are not always on here 24/7. If you find a bug in the software and you want the developers to see it quickly, your best course of action is to report it directly via their bug report link. Additionally, in the forum, you can tag @martin, the main developer of the software. This will bring your issue to his attention more quickly. You can also email your bsdesign file to the developers and they will check to see if there’s anything wrong with it.
The software will never automatically add max-width media queries because as of Bootstrap 4.x, Bootstrap became a mobile-first framework. Anytime you add a media query via the Styles palette, it will take note of what screen size (breakpoint) is currently selected, and add a min-width media query coinciding with that breakpoint. For example, if your workspace is set to LG, the media query added will ALWAYS be @media (min-width: 992px). If your workspace is set to SM, the media query added will ALWAYS be @media (min-width: 576px), and so on. There is nothing random or buggy in how this works. It’s consistent and predictable. You can always double-click the actual media query in your CSS and change it if you want a different value.
I personally have never encountered an issue where the Navbar toggle or Tab Component works in BSS but not in the browser, but when issues like this arise, they are often the result of some code that was added, changed or deleted inadvertently that changes the default behavior of the Component. This can be quickly and easily confirmed by creating a new design, adding the component in question, and testing to see if it works. If it does, you have to do some detective work on your current website to see what you did wrong. If not, you may have discovered a bug.
FWIW - I can appreciate how a software bug can cause one to become frustrated, but I can assure you that profanity laced rants and idle threats about “switching to different software” and “not paying another dime” won’t get a bug fixed more quickly. (They certainly won’t endear you to other forum members who might otherwise be inclined to try and help you.) This forum isn’t moderated per se, but we do all try to help each other, and we appreciate members maintaining a certain level of… professional decorum… within our little BSS family. The old saying, “You’ll catch more flies with honey than vinegar” is particularly relevant when you need help here. 
Bootstrap Studio is actually an outstanding piece of software, but like all computer software there are occasional bugs. I can tell you after 40 years of using computers that the developers of BSS are some of the best, most dedicated, most responsive people I’ve ever encountered. They often fix program bugs the same or next day (which is practically unprecedented in the software industry.) I’ve seen Adobe take YEARS to fix bugs in their products.
Lastly, I would recommend that instead of “throwing your laptop out the window,” you make sure the program’s backup feature is enabled, and set the frequency to 5 minutes when you are actively developing a website (so you don’t have to use CTRL-Z to undo hours of work.) You can always do an instant backup before attempting something complicated (either via the menu (File > Backups > Backup Now, or by hitting CTRL+SHIFT+Z.)
A+