Same here. LibreOffice is terrific and rely on it heavily. But no matter what icon set I use, LibreOffice is still ugly as sin.
I found this on a video which seems to be on Windows. Looks pretty clean:
The real horror show is the MacOS version:
File compatibility for documents with advanced formatting is still lacking. In those scenarios, I've started using OnlyOffice. I have a Micrsoft365 subscription, but MS Office on Mac OS is a terrible experience for me, so I'm glad to finally be in a position where I don't need MS Office. (OneDrive space included is the primary reason I still have that subscription)
Why not go full time OnlyOffice?