Are there any good in-browser alternatives to Sketch (https://www.sketchapp.com/)?

It's time to upgrade the laptop. All of my current tools (except Sketch) will either run natively, or have highly functional alternatives on linux. It is the one app that still binds me to macOS. Without going doing the hackintosh in a VM route, has anyone found a workable solution?

(Based on previous experience the Gimp / Inkspace combo is not an equivalent. Happy to be corrected on this though).