You can negotiate part-time work.
1. This is easier at your current job, since your company knows you, and also you have organization specific value (code base, procedures, people).
2. It's also easier at companies that value your output, not how many hours you sit in a chair. Companies that support remote employees well are good for this.
So, your best bet is actually negotiating at your current company.
Some things to keep in mind:
- Half-time is harder to get than e.g. 4 days a week.
- In US requirement for employer to provide health insurance (for larger companies) goes away for employees working less than 30 hours a week.
- Some company health insurance plans in US won't accept employees working less than 30 hours a week.
I've done an interview with someone who has been working 4 days a week for past 15 years, which'll give you some sense of what it's like: https://codewithoutrules.com/2018/01/08/part-time-programmer...
And I'm working on a book on how to negotiate a 3-day weekend (and more broadly, shorter work hours): https://codewithoutrules.com/3dayweekend/