Hi Leo,
Thank you for your additional information, if you are using two Renaisser brand pens, then perhaps I recommend you to contact Renaisser customer support about this issue. Because we don't know much about this brand of stylus, the screening process that applies to the Surface Pen or Slim Pen does not necessarily apply to this model of pen.
While Renaisser's customer support informs you that their pen is Surface compatible, after all, this is a third-party device and we cannot guarantee you its compatibility. In fact, a very easy way to test this problem is to try testing it on another Surface.
But the trouble is that your old Surface is broken. If you are near a Microsoft store or sales outlet, perhaps you can bring your pen to the store, explain the purpose of your visit, and test whether the pen will work well on other devices.
In addition, I have a very important information to inform you that Surface Pro 11 has an obvious difference from most other models of Surface Pro, that is, the device is ARM architecture. I don't know if you need a dedicated driver for the pen you're using, but if you've ever used a Surface Pro with an x64 or x86 system, you usually won't encounter a failure to install a driver. However, the lack of adaptive drivers for external devices is a problem that will occur on the Surface Pro 11.
So if you can still get in touch with Renaisser's customer support, it's worth checking with them to see if their pen will work on an ARM device.
Best Regards,
Mitchell | Microsoft Community Support Specialist