Not a bad try, for you. Here is why you are wrong. First, as a practical matter ask any defense atty over beers whether or not
their client is in fact guilty when they bring a suppression motion and if you pay for that beer, they'll say 99% of the time.
So in short, yes, it is admitting guilt but getting off is the penalty the people pay for illegal searches. And 2, the analogy between an
illegal search and a legal subpoena is loose. Show the subpoenas in question are illegal. The statute authorizing congressional subpoenas
is crystal clear, executive privilege doctrine as it has evolved is not clear at all, and the last word on it saw Nixon getting unanimously rat fucked
by Scotus.
Bottom line is this is a bad faith stall tactic and everyone knows it. You simply won't admit the obvious strategy, nor would I expect you to.
That would undermine the strategy and would be admitting it's just a sham, corrupt intent and therefore obstruction of justice.
But desperate people do desperate things, and this is an admission Trump has his back against the wall.