Same but I have only been doing this 18 years. Is the drain plug aluminum? I also found I have to use a 6 pt socket or it's a no go.I've been doing DIY oil changes for over 35 years so I have done literally hundreds of oil changes - Hondas, Toyotas, Suzuki, Subarus - including most of the 43 lifetime oil changes on my 2010 Forester that has a 17mm oil drain plug. I never rounded or damaged an oil drain plug until my first oil change on my 2018 Forester with the dinky 14mm head. I've used the same wrench set over these DIY decades so I don't think the problem is cheap tools or lack of experience.
After rounding the Crosstrek, I switched to an oil extractor and never touch the drain plug.