Phen

Hi @Phen,
The crash is occurring due to an issue with the Text Layer on Page 1, after deleting this i've successfully been able to open the file in Publisher - see attached.
I've now reported this issue over to the developers.text layer deleted.afpub

App: 1.10.4 OS/HW: Windows 11, NVIDIA RTX3080. Renderer: tested both hardware acceleration and WARP When I hover over any UI elements, they become completely broken / obscured by glitches.  
This bug is reproduced on all Affinity Suite apps (Designer, Photo, Publisher) and affects both renderers.
Update: found a solution in another thread. You need to open Windows Services and Stop+Disable "Nahimic Service". I don't even have any ASUS/MSI hardware, no idea where it comes from.

Welcome to the Serif Affinity forums, @Phen.
Publisher runs on Windows 7, 8.1, and 10. As far as I know Windows 7 does not have a spellchecker, so Publisher would not be able to spellcheck on Windows 7 at all if it depended on the Windows 10 functionality. By using Hunspell instead, Publisher is able to do spellchecking on all the Windows releases that Publisher supports. I don't know for sure if that's the reason that Serif chose not to use the Windows 10 function, but I think it probably is.
If you want Publisher to spellcheck in a language it doesn't currently support, and that language has a Hunspell dictionary available, you can download it and install it yourself. If you search the forum for the word Hunspell you will find several discussions of installing Hunspell dictionaries.
But specifically for your need for Russian, you should be able to download the Hunspell Russian dictionary files for LibreOffice and install them. You need these 3 files: hyph_ru_RU.dic, ru_RU.aff, and ru_RU.dic.
If you open Publisher's Preferences, the Tools tab has an entry at the bottom showing you the directory where you can put additional dictionaries. Click the Open... button. In that directory, create a new directory named ru_RU (or, if that doesn't work, try ru-RU) and place the 3 dictionary files in it. Restart Publisher, and you should then be able to specify Russian as a spellchecking or hyphenation language.