Is it possible to change the cookies stored by the browser, desktop application?

Question

Browsers

The browser stores cookies downloaded from the Internet (such as session cookies) on the hard drive. It is clear that they can be changed by the site that provided them.
Question:
Can these cookies be changed by an application running on the desktop - in parallel with the browser?
Sub-questions:
1. Is it physically possible to do this - are there any Windows security restrictions? (Would Windows consider such an application to be malicious.)
2. Is the browser preventing this? After all, this is its database, and a third-party application will change its data. Doesn't the browser (Firefox, Chrome, IE, etc.) check the integrity of the database? Is it possible to change these cookies while the browser is running?
3. Does such an application have to be a browser extension or can it work as a separate application from the browser?
Note:
Physical location of cookies (different for each browser):
Firefox
C:\Users\Username\AppData\Roaming\Mozilla\Firefox\Profiles\db2laujv.default\cookies.sqlite
Chrome
in C:\Users\Username\Local Settings \Application Data\Google\Chrome\User Data\Default
Cookies and Login Data (untested)
Internet Explorer
varies between versions, in particular C:\Users\Username\Cookies

Answer 1

1. Yes, it is possible, there are no prohibitions.
2. No, you can even take cookies from one browser and place them in the same browser on a different computer. And the server will think that you are a different person. As a matter of fact, partly the sessions were invented for this, otherwise it would be possible to steal access without knowing the password in this way (By the way, some guys do this)
3. No, it shouldn’t, I’ll even say more, there are ready-made solutions for Google and Firefox for Google, if memory serves, it's called Magic Wand, although I could be wrong. By the way, I’ll even say that in different browsers there is almost the same structure, they usually sometimes differ by changing the columns (those that were vertical became horizontal, and those that were horizontal became vertical)
It is worth adding that important info is most often stored in md5 for decryption, which is promised a Nobel prize. But the question was after all in changing the data;)