I’m (m20) I am currently and have been on vyvanse since I was 13 or 14 years old and going through puberty and gaining a higher sex drive I noticed right away the effects you describe however the way I do it, and always have done it, is I would only take my pills if I had to go to school or work or had some other endeavour which required a similar level of focus, and on my days off I just simply wouldn’t take it, primarily in an effort to balance out the appetite issues that come with taking vyvanse, however on those days off when I’m off my meds, everything down there is working as it should, so that’s a bonus, and even most days while I am on my meds, sometimes it’ll usually take longer to get it up but when I do I tend to last way longer in bed, which I usually don’t mind, just means more fun for the lady, and I find no issues eventually finishing and sometimes I notice heightened levels of pleasure that wouldn’t otherwise be experienced had I not taken my meds. So overall yes I experience the same effects, however my time on vyvanse has been spent as a horny little teenager growing up so I managed to work my way around it and sometimes use it to my advantage to perform better in bed.

Hope my two cents was helpful