If you disagree with what I write, you might contemplate on how we all only do our best with what we think at the time.
I have read somewhere that Ki is not necessarily the same as the chi as in tai chi, but for our purpose here it will be, because the so called internal or soft arts have similar principles.
Perhaps you might consider this:- Aikido at its heart is not the manipulation of the physical but victory over self in avoiding the physical.
If you can feel your own power ... so can they. Your true power, and great it is, emanates from the use of your mind. Expanding ki requires relaxation ... if there is no relaxation of the big active muscles, then the attacker feels the attack in a way that they can counter (if allowed by dojo or style rules).
Extending ki is important in all directions and not just in one or two as you might feel in ‘unbendable arm’, then the body is unified and has optimum power. However, this power comes from the muscles joining in willingly and not being coerced into working. Done correctly you won’t feel them working but will realise their effect.
Respect the energy of the attacker, harmonise, reduce your own tensions in order to extend ki. Relaxed but extending your spirit energy outwards you generate power but retain the opportunity of speed.
Any exercises carried out for aikido practise should engage consciousness, or you miss an opportunity to develop the mind / body connection.
Even at home, perhaps reading this, a beginning exercise is to sit in chair and explore the space around you – with your mind, be centred and relax outwards, put no limit on how far you believe you can reach with your mind .... be balanced, all directions, always. Do not be afraid of using your imagination.
Be sensitive ... attitudes like caring, allow this to manifest your power and subtle influence to neutralise an attack ... wanting to defeat the other is counter to the spirit of aikido ... it’s why the art is so difficult.
Many will not choose this advice, some because they don’t quite understand, some because they don’t want to. Perhaps some though have already moved beyond this level.
If your mind set is to conflict with others and that you can beat your attacker ... you have already thrown away your sensitivity to change and it is unlikely you will find the magical takemusu moment ... something that appears without plan or intention, out of nowhere ... but only if you are aware.
It’s hard to find something if you don’t look for it . . . unless of course you are exceptionally gifted with luck.