I’ve heard parents say that being a mother or father is a thankless job.
However…
These same individuals wouldn’t trade it for any other job in the world.
Thankless jobs can be Pleasurable Wonderful and Meaningful.
Thankless jobs can be jobs that one would never trade for the most thankfilled job, such as a global good-news-delivery-person with fantastic comprehensive lifetime benefits.
And imho, infinite thanks and gestures of gratitude still cannot compare to the thanks that they are due in this world.
It sounds like the OP is referring to people in thankless jobs behind the scenes that as a community we all benefit from yet IRL may not realize how much they do for us personally.
Also, these jobs don’t come with the compensation of status or power.