Second one better, but for different reason to those stated. Sometimes people are tongue tied. Or they are trying to speak in a language that is not their first language. An innocent slip of the tongue is not causing damage. So why penalise? As an aside, one world class player said "pity" when dummy came down, more to herself, and the person in third thought they said "petit". The upshot was they played a card out of turn.

Isn't this situation covered by 46B4?

When it is a notrump contract, the designation of a trump is invalid.

The question though is if the TD should investigate which suit declarer thought was trump, and then the lowest card in the suit should be played (because of the parenthesis in the beginning of 46B).

This problem is not solved by adding suggestion number 2.

... and I dislike suggestion number 1.

I would add 46B4 (pushing the current #4 to #5 and the current #5 to #6):

If declarer calls for a “Trump” in a No Trump contract, the call is invalid and declarer may designate any legal card (except when declarer’s intention is incontrovertible)

Please note that the same qualifier in the introduction of 46B is protecting declarer, but the suggested one above is protecting the defenders

One effect of the second alternative is that it's always better for a declarer to say "trump" rather than "spades" (or whatever declarer thinks the trump suit it). So declarer can benefit by not using the recommended form of designation in Law 46A. (Although existing Law 46B1(b) about "winning" the trick isn't very good from this perspective either.)

Also, if we go with the second option, we'll need to figure out what the effect should be if declarer calls for a "trump" of a particular rank. Is the entire call void (analogous to Law 46B4), or do we apply Law 46B3?

I would prefer the second alternative.

I really don’t like to force a play from a the suit “to dummy’s right”.

A good partner will usually not put a suit that could be confused as trumps on the right in a NoTrump contract, but declarer might still be confused and call for a “Trump”, even when that suit is not “to dummy’s right”.

In a perfect world, If “Trump” is the only qualifying designation, the director would be able to establish, based on the auction and the play, which card was intended, and force the play of that card.

I don’t believe this is practical, so voiding the designation is better, but adding the qualifier “except when declarer’s intention is incontrovertible” is best.