There's two types of straps. Elite style (face clamping) and Halo style (less face clamping). Looks like the Maecker is Elite style. You could consider the BoboVR M3 Pro? That's Halo style and you might find it more comfy.
By the way, I emailed Kiwi Design yesterday asking if they made a battery strap yet and received this reply today,
"Dear Customer,
Thanks for your contact.
Our Battery Head Strap for Quest 3 will be released on Nov. 27th, but only available on our website, you can wait for it. And it will released on Amazon UK around Christmas, so you can buy it on our site, which will takes about 10 days to UK.
Best Regards,
KIWI design team"