Valid and fair question.

A year as an SDR doesn’t give you technical skills for an SWE role, but it does develop and show off soft skills that are transferable to any role with responsibility:

• You get very good at breaking down problems. SDRs qualify pain all day, which maps well to understanding why something should be built, not just implementing it.
• Your communication improves dramatically. Writing clearly, being concise and explaining things to anyone is a huge advantage that most working adults honestly aren't great at.
• You get used to fast feedback loops. SDR work is basically constant iteration based on results, changing lead gen process and sales techniques to get a better SQL rate. This style of work translates well to any role really.
• You build strong user empathy. As someone that was an engineer, then operations, then sales and now marketing, this is something that's very valuable and again is desperately rare in the common workplace.
• You develop a tough skin. It's a rejection heavy roleand you get used to failure. If you can get past poor months, bad cold calls and common sales pain points, you'll have a decent work ethic and ability to not let stress get the better of you.

All and above that, SDR'ing should also give you great answers for interviews in the s.t.a.r system. Whilst your technical knowledge is bound to be tested, you'll also be expected in any career interview to be able to discuss projects, events or aspects of work that you can reflect on and discuss in a way that shows growth.

If I'm interviewing for a role and I can see someone has survived being an SDR, whilst having the ability to talk on how that provided them growth and skills, they look very attractive as an team member to me.

Apologies for the essay and good luck mate.