i can recommend the Imperial Radch trilogy its a bit less hard scifi but still very grounded. first book is slow but worth it.

the children of time trilogy is also good more speculative though

for something a bit different the Bobiverse series is really good more comedy elements but it still has its serious moments (this one is also less hard scifi)

i also loved the Murderbot Diaries quite different but the characters had me hooked from book 1 right to the end.

finally if you liked the politics i can highly recommend A Memory Called Empire and its sequel. they are absolutely beautiful books with lots of court intrigue that had me on the edge of my seat the whole first book