(Hello, I deleted my first comment because I didn’t noticed that only an alternative to Publisher was sought. But I came to the conclusion that It could help someone, so I leave it down anyway)
For Publisher, LibreOffice Draw and Scribus are the best. With LOD you can also edit PDFs.
You may also try Krita or Inskape for some documents… perhaps… (I use them to make brochures or posters, but my approach may not be as pragmatic or very practical as they are for visual editing). I don’t really use Publisher for anything else, with a little more, even in the text editor you use…
Softmaker Text is also good for the format, it doesn’t break down as much as Microsoft so it could also be an alternative for both Publisher and Word (but that’s just me that I’ve adapted to making constant edits in variety of programs, who knows, i’ve also could work on LibreOffice Writer and use it like Publisher indistinctly).
I hope it helps. Then I leave my first comment out of place in case the flies.
For Microsoft Office, Softmaker Office is the best one, the interface is almost the same, functionality, location of items, 3D rotation or things like that…
I bought a license with a Manjaro coupon that gave the full license to 50%. Manjaro gave the coupon in an announcement on a stable update back in December, it’s one-time purchase, it should keep working. You can redeem it here.
Actually, I Love LibreOffice but I need Microsoft Office compatibility in my work, but this alternative is lighter, prettier, cheaper and for me they’re pretty much the same (except for some keyboard shortcuts but nothing hard to get used to). I haven’t had any compatibility issues. Bad thing, despite, is that you only have the 3 basic office apps but I hadn’t noticed this, as Publisher is a little particular.
Of course, that license is a one-time purchase, it lets you share it up to 5 devices (non-existent systems) but there are also subscription versions and a free one with limited features.
As the other comments say, LibreOffice may be an option (and one of my favorites, maybe I would also add OnlyOffice, but for me it’s slow it doesn’t just convince me.