First of all: ASAP? You're talking about a trillion dollar program that would take centuries. We can't even feed the people on
this planet or stop murdering each other for 5 minutes. Why is it of such utmost important to detect something vaguely out there?
Second: I'm not sure why you're asking about fossils and debris? The size of space is so big that the most advanced state of the art is to detect atmospheric compositions as a whole. How would we possibly be testing for microfossils"?
If you mean on more local places like Mars, there's pretty good evidence Mars has/had a microbiome. But without better proof, it's not like they're going to make announcements. The rovers make deliberate choices on what experiments it carries and those devices need to withstand the trip and justify the shipping/opportunity cost. They don't have an electron microscope, but they have tried other methods of identifying life. A small ETM is planned for a future mission, though.
And to wrap it up: you're assuming life would want to be found. Space is unfathomably big, but it's also unfathomably old*. Humans won't be recognizable if we survive a few million years. How about a billion? What results may not even seem like life as we know it all. Their home may not even exist anymore, and they move through the interstellar medium. We can only look for known signs of bioactivity right now... not, say, crystalline beings in stasis ships traveling the void with virtually 0 energy emissions.
Or maybe they just realized it's a waste of resources - what would one even have to gain compared to lose? They may have made horrifying weapons that have no countermeasures and hide, knowing any first contact could kill their entire people.
And if they're sufficiently advanced, why not just create digital heavens and live in bliss and excitement for, essentially, eternity with their families and friends? Why look out into a void for aliens they probably could never understand when they can have cool space adventures with sci fi technology in their Matryoshka Brain?
All this is, is a neat thought. You're letting it get to you, but it's genuinely not important. Smart folk are trying, but it takes a long time and the odds aren't in favor of your life changing in even the smallest way from the endeavor.