Website themes vs hosting plans

Hello! I’ve finally purchased two stunning themes on Envato for upgrading my websites. But to my surprise it seems that the PHP settings for post max size, time limits etc are too low to match the required levels of my new theme. I contact the seller/design team who says that it’s just to ask my domain host to increase them. I contact my host (Siteground) and they tell me this is only possible if you have a cloud hosting, and not for websites on shared plans. I get back to the design team and they confirm it’s like this, most premium themes need more than a shared hosting plan. Bottomline: a normal, not corporate business that have less than cloud hosting can apparently not install the premium themes that Envato sells! There is absolutely no accessible information anywhere about this when purchasing a theme. I’m not new to setting up websites with Wordpress but have never seen this info anywhere! I can’t imagine that most small businesses buying a Premium Wordpress theme have a cloud hosting plan? I think this should be stated clearly on Envato/Theme Forest website and along with the basic information about every theme on their individual presentation page. So my question is: is there a work around or can’t I use my new themes? Thank you!