Hi Superfluffy, thank you for posting in Apple Support Communities.
Can I suggest that you update to the latest iPadOS 15.3.1 (if you have not done this already) as updates can help resolve some problems. The following link can help you:
https://support.apple.com/en-au/HT204204
Can I also suggest you check your predictive text settings again as per the following linked article:
https://support.apple.com/en-au/guide/ipad/ipad736a3ca8/ipados
Can I further suggest you disconnect (Forget this Device) your Bluetooth Keyboard and reconnect it again.
If the issue is not resolved by the above support articles and suggestions, you can make an appointment and have your iPad inspected at an Apple Store or AASP (Apple Authorized Service Provider). Please use this link to find one in your Country Apple – Location Selector. After going through the process, you will be given all the options available.
You can also contact Apple Support as follows: