Hello Sascha,
I doubt this is the right place to ask for this kind of support, but I’ll give my opinion on this.
If you are using WooCommerce, and you have plenty of products with somewhat a lot of attributes/variations, then 250-400 queries are somewhat alright, but 400 is on the higher side.
You can show less information on product archives, if by “per page” you have in mind product archive pages or a single product page.
Another way to reduce queries is to show fewer products per page.
If you know the code, and you use custom fields for certain parts of your website that repeat on every page (say social links on the footer or header), you could use transients.
Using some sort of caching helps a lot for dynamic stores, so even if you would have a higher number of queries when logged in as admin, visitors on the frontend would be using static pages, which would be fast, and would take the load of the server.
A few suggestions, but it always comes down to what theme you use and how well it’s coded, as well as amount of plugins (number might not matter, but if there are a few plugins that do things on each page, that they shouldn’t do, it adds up, and the more plugins you have, the bigger the chance is of that being a case here).
