The question is why a company would wish to hire someone who is only available during a short window in late afternoon for sales? That needs a stronger answer than "I'm a developer working on an unrelated product who would like to gain sales experience but only as a side hustle", because sales engineers and product managers who love talking to clients are willing to make themselves available when the clients want the meeting, not when they've finished their real job.
The more obvious way for technical folks to break into SaaS sales is to be interested in contributing to the sales effort of the company that also employs them to write the SaaS. If that involves a different employer or renegotiating their compensation package to add in bonuses... well see it as practice.