I am getting no younger and don't want to waste time and damage my joints for no purpose.
If people in your dojo are damaging your joints, then I'd say that they have completely missed the point and are not practising Aikido.
Many folk don't understand that they have a duty of care towards their ukes, and get focussed on improving their interpretation of technique to the exclusion of everything else
Some folk are downright sadistic and enjoy inflicting injury
To practise Aikido one must develop a spirit that is above all compassionate, and also dedicated to allowing uke's force to become his undoing, which takes a great deal of understanding of the person attacking you (and I'm not just talking about mental understanding here!)
There are relatively few people who train this way, but there are enough and their numbers are growing
Choose to join them and it will open up many new dimensions in your training