Thing is, dying isn't the worst tactical option here.

There is a chance buying the farm will just throw Harry into the horcruxi. Not certain enough to do it deliberately, but enough that any plan you come up with has to be better than the option of

"Do nothing, die, hope to hang out in the horcruxi until Voldemort buys it again, let resonance remove you both from play"

Which is a non-negligible bar to clear. Telling him a trick which might be the power he knows not to buy another minute of breathing doesn't pass muster. Telling him of the possibility doesn't pass muster.

There are very few things which are both true and acceptable to tell Voldemort, simply because any information you give him, he will use against the world. If you give him information he can't use, he will ignore it.