It's a tough one in respect that when a not too high wall of water comes toward you, a natural tendency is to want to lift your paddle up and over it - otherwise it will catch a bit. And then if you keep the paddle lower next time, you can really get smashed on the nose or face by the paddle loom. So it's a learned response to change all that and to do as you do and spear the paddle somewhat into the approaching wave - and it you then get thrown back, try to crunch down more, maybe move your hands closer to the foreward blade so that it feathers more like an arrow - and read and try what others do in the same situation:
some other places to ask:http://boatertalk.com/forum/SurfZonehttps://www.ukriversguidebook.co.uk/forum/viewforum.php?f=36
For the twisted high offside arm situation, one thought is to move your blade a little higher up the wave face so that your outer offside hand can be a little lower - that way the stretch won't be quite so much, but probably the best thing to do is gentle twisting/stretch exercises at home so that you have more motion or at least resiliency when the problem arises.
And of course, the other obvious thing is to look closely and choose slightly more gentle surfing locations and situations because surfing is about fun: I think that surfing is just about the most paddling fun you can have for free [but you actually work harder for it than most other paddling, heh heh]. For [like me, not you] less able folk, it's not about the most dramatic conditions but about being out there and intentionally enjoying the experience: some of my most rewarding paddling and surfing experiences have been under extremely benign conditions.
[edited to add: other strategies to use are to choose the smaller waves so the stresses are lower or to take off further out and pull of earlier before the waves get steeper in the shallower water - in both those cases the paddle out will be a little less severe]