My experience was that the dpi and everything else would reset itself after reboots and I'd have to launch the software for everything to work again, even if I set on-board memory on. Super annoying and may be the same thing causing your problem.
I believe the g305 works with the old logitech software, which is much better than ghub. You should give that a try and see if it solves your issues with having to launch ghub just to get your mouse to work properly. Here is a link: https://support.logi.com/hc/en-ca/articles/360025298053
The g305 does work with the previous software, but my Logitech steering wheel does not :( So I'm stuck with the new and terrible G Hub. Hopefully I can ditch the Logitech ecosystem whenever I get around to upgrading to a Fanatec wheel.
I believe the g305 works with the old logitech software, which is much better than ghub. You should give that a try and see if it solves your issues with having to launch ghub just to get your mouse to work properly. Here is a link: https://support.logi.com/hc/en-ca/articles/360025298053