Create your own keyboard in the game and no need to worry about any of this

Every time I upload a new version I delete all files and then upload new ones.

Because newer version may have differently organized sprite sheets, I guess, while naming remains the same, you may get cached files shown instead of new ones and they don't fit the newly exported version.

Basically you have something like shared sheet 0 in your export, but now it contains different images, so it looks like nonsense.

This happens even when not dealing with cached files. I guess game code may point to images on that sprite sheet and if you only upload new script files ( after a minor change ), or try to rewrite files, they still may come out wrong.

Therefore nuke everything, then upload a new version.

Not much you can do for people who already have the game and get served rong cached files ( other than tell them to empty their cache )

Bear in mind as Ashley has mentioned, there are no guarantees that standalone desktop apps will continue to work in perpetuity. This might of been more true a decade ago but software is a lot more sophisticated now and Windows/Graphics driver updates can easily break the functionality of software

It's still true. Even if updates break something, you roll them back or keep one PC with older versions of windows and drivers just in case. Besides nobody serious about their work just updates windows or drivers on their main workstation before making sure it won't break things.

Have 3 arrays instead

One with DF, another with MF and third with attackers,

Then another array with the final team

Keepers should always be the first ( 0 ) in the array

So when you choose for example a 4-3-3 formation fill the next 4 spots in this final team array with values from DF array, next 3 spots with 3 values from MF array and final 3 spots with 3 guys from AT array.

There is one important difference here.

With non subscription software you actually can use it forever regardless of what windows updates do.

For example I still have a laptop with Softimage running windows 7 on it and as long as that laptop works it will continue to work even though Autodesk killed it off in 2015.

With their current model I believe you'd be out of luck. You want to use Maya or 3ds max? you have to keep paying forever if you want to use it

I guess that would be the difference between Construct 2 and 3.

Since soccer jersey numbers usually go from GK 1, defenders 2,3,4 and so on, wouldn't just sorting that do the trick anyway?

I mean, since GK is #1 he will always be on top and defenders are usually wearing 2,3,4, so would be next in line

If you can really draw graphics like those then there will be no problems as far as developing a nice looking game with parallax scrolling and all that, but you will definitely run into a wall when trying to do realistic water effects, simulations and similar stuff. Probably no way around it, but maybe sort of climb half way up the wall with some tricks

If you converted them to webm yourself, try importing a wav file and let construct convert it for you

I edited my post above, but if you don't see it try this first

Open one of Construct's sample games, import your audio file into the game and find where music starts in the sample game, then edit the action to play your file instead. If your music does not play there then you know your music file itself is the problem.