American who moved to Switzerland 1.5 years ago and learning High German (now in A2). Hardest thing for me right know is knowing when it is appropriate to use

American who moved to Switzerland 1.5 years ago and learning High German (now in A2). Hardest thing for me right know is knowing when it is appropriate to use the Akkusativ versus Dativ cases. Declining is always difficult, especially considering that adjectives are declined and also this declination depends on the presence and kind of article (which is also declined). I love Switzerland but since I am learning High German it means the Swiss are more likely to talk English to me if they know it (completely understandable, given the relationship between High German and Swiss German). So practicing is intimidating or can feel rude if I try to stick to High German in this case.