Chess will never be solved, here's why

25 knights versus 10 queens is a win for the knights.
Unless you split up the knights ridiculously or start their King off easily matable by the queens.
10 knights versus 5 queens?
That's better - the issue might be if any of the queens can trade for two knights.
Can the King with the knights be free of checks including from the rear?
If he has eight knights around him he can use his extra two knights to replace taken knights?
That one's much less clear than 25 versus 10.
20 versus 10 should win too.
Fifteen?
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but this is all off the forum topic - which concerns the recognized form of chess.

wuznt there a game where there were (6) queens on the board in a grandmaster game ?

Yes, there were a few master+ level games where more than 4 queens appeared on the board (The Tigran-Fischer game was 4).

http://www.chessib.com/five-six-queens-chess-games.html?i=1

There was an 'Immortal Game' with a lot of promotions.

🤔

I thought it was this game.
But apparently not.
https://en.wikipedia.org/wiki/Immortal_Game

Obviously I didn't start with positions like that nor this:

But that's why we want tablebases.

The position of the pieces is often going to matter when the material is roughly balanced! Even if you ensure the most obvious factors are avoided (eg pieces en prise or rapid forced mate)

In backward order.

E.p. positions need to be taken into account while building a tablebase, but I think once built all the e.p. positions could be deleted (giving a very minor saving in space) because there will never be more than a trivial forward tree before all the leaves are non e.p. positions in the same or a child tablebase. The accompanying routine that returns the results could incorporate a forward search to assign values to the e.p. positions. This would hardly make any difference in the response time for existing tablebases.

I notice that my previous response seems to say this is done, but in fact I don't know if it is or not. You wouldn't see any difference in the output.

I still don't understand how you are proposing to convert a tablebase that weakly solves competition rules chess into a strong solution in an easy step. The idea of a strong solution is that it gives a solution after suboptimal play and Syzygy already does that if the repetition rules are dropped.

An "on the fly" strong solution is, I think, practicable for Endgames with a few men. E.g. although a tablebase that gives a strong solution of KRK is impracticable, that's because of the number of fp-positions in the Endgame. In play, if a solution of an fp- position occurring after non-Syzygy play (whether suboptimal or not) is required then the 9.2.3 positions that have been repeated are known. A modified DTZ50 generation procedure that stops generation at those 9.2.3 positions and any 9.2.3 positions not marked winning in Syzygy (and not those marked frustrated wins) should give a weak solution of the fp-position and hence represent a strong solution in play. You would also expect it to run at least as quickly as a DTZ50 generation which for that Endgame is probably within some practical time controls on a decent machine.

A tablebase is a strong solution of some variant of chess. Basic rules is the simplest. I think basic rules with an n-move rule is fine too. The one needed to get a strong solution of FIDE rules chess is absurdly large and not very interesting to me.

Perhaps it makes more sense to observe that we have tablebases that give strong solutions of a lot of small variants of chess with up to 7 pieces, for basic rules and (if I am not mistaken) chess with an n-move rule. And not for any with a repetition rule. Even 3 piece versions are demanding (I recall finding the complexity of one type was surprisingly large).

so long as by "n-move" you mean "50-move".

A lot of info about 3-fold repetition and 50 move rule in the two Wiki articles on them.
I didn't see 'competition rules' anywhere'.
Chess.com and Lichess both mentioned.
Apparently 3 fold repetition didn't get started till the mid 1800's.
The article on it here:
https://en.wikipedia.org/wiki/Threefold_repetitionBut there's a flaw in the article.
I'll mention that in a minute.
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The 50 move rule here:
https://en.wikipedia.org/wiki/Fifty-move_rule

Its not clear when 'competition rules' would not apply.
Whether FIDE or USCF.
In an informal game of offline chess that is not part of a tournament and not rated? Maybe there's a less vague explanation.
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Here's the flaw in the Wiki about 3fold.
"In chess, the threefold repetition rule states that a player may claim a draw if the same position occurs three times during the game. The rule is also known as repetition of position and, in the USCF rules, as triple occurrence of position.[1] Two positions are by definition "the same" if the same types of pieces occupy the same squares, the same player has the move, the remaining castling rights are the same and the possibility to capture en passant is the same. The repeated positions need not occur in succession."
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How could the 'possibility to capture en passant' stay the same ???
Lol.
Quite a slip there.
But otherwise good articles.

Usually the case when the initial position has no possibility to capture en passant. Not too often otherwise.

How about Never otherwise.
Or Nevers. Bad English?
The modern version of chess got formalized in France I believe.
After Philidor in the 1700s'.
But there's a town in France called Nevers I think.
Probably pronounced neVayrrr.
En passant situation repeated three times?
Nevayyyrrrrr !!
Simples?
Never's.

f4 does not block the check, it's as simple as that