Hello!

I have been working for 2 weeks on a file (see attached). I understand that for you, professionals in Excel, it will sound risible that a person can spend so much time on such file, but for me, as a beginner, it did take a lot of ,a truly lot of effort to come up with this result. Initially I have started it for a simple reason to learn Excel as it is very useful, and it did turn out to be very interesting and challenging.

On Saturday night I almost lost the whole work, but have managed to recreate the file. And now I even think that I might use it at might work, although no one, except me, needs anything of the sort - everyone and everything is on the cloud, and on a customized software.

Still, I would like to optimize it. Please, take a look at my questions and issues I have with the file. I will be grateful for your help and your opinion. I did put the copyright sign there, but it's merely for fun, and, of course, if any of you find this type of file useful, I will be happy if you use it for your purposes. And also, I used lots of templates I found on the web to come up with this result.

1) The file is very very heavy - 16MB. For your convenience, I am attaching a much smaller version of only 3.2 MB because I have deleted 8 additional tabs, which are completely the same as tab1 and tab10. This size seems to be absurd. All these 16MB come from formatting and formulas. How can I optimize it? How can I decrease the size while still keeping nicely looking formatting with those interesting features I added?

I couldn't upload it here, so I put it on the google drive - here the max size is 1000KB.
File

2) Formatting is changing constantly by itself; I can't predict when and how. It can change when I change some cells, or when I add rows, or just when I open the file on another day. Drop-down lists also can change. And that happens seemingly on a whim (of course, not on whim, but as I don't know the reason, it seems to be like that).

Thank you very much!