Hi Apollwn,

Good to hear that you are doing well despite the injury at your biceps.

How do you know you completely ruptured your biceps tendon? Did you have an ultrasound scan/MRI? Sometimes some fibres remain attached, maintaining a good level of function. For example, many people have their rotator cuff tendons worn out/torn without knowing it.

It is difficult to say about your future. Some people deal with that perfectly while others may need surgery (maybe to other related locations, not necessarily at elbow joint because of changes of the physiological biomechanics).

Biceps brachii is a key muscle for elbow flexion and elbow supination therefore, an exercise protocol to properly restore these movements may be needed.
Yes, biceps brachii is also an important muscle for shoulder stability/motion so an exercise protocol aimed at the shoulder joint may be needed as well.
The fact that you are are doing well functionally, do not have pain and have limited weakness are good factors for recovery. However, I reckon that a physio assessment will help you better understand your case.

Let us know about your case.

Regards