Saber should be exactly what you need:

https://github.com/saber-notes/saber?tab=readme-ov-file

You can take handwritten notes and supplement them with text and images. It can also sync directly to your Nextcloud Account or sync via a Saber Server from the developer.

I used it for a while on my Boox tablet and it worked really well without many bugs or hiccups. I only switched to Notesnook because I stopped taking that many handwritten notes that had to be synced as well.