So sorry to hear your LO was poorly for so long
and great news he is recovered
It seems totally understandable to me that his self feeding won't have come on the way you might expect. Is there anything at all he will self feed? I'm not suggesting you turn to totally unhealthy foods but would he for instance be tempted to pick up and self feed a pancake, cup cake or muffin? (there are some healthy sugar free recipes with fruit and even veg in the recipe, even some made with white beans and eggs which are healthy and tasty) most kids are usually tempted by cake, I'm just thinking it would be a starting point, to encourage him to self feed.
When you say he won't take lumpy food, are you offering lumpy/puree/mashed or is the 'lumpy food' proper finger food (not mixed with puree at all, not mashed at all)? Some kids just don't like lumps and don't like 'mixed' food but are happy to take finger food, 'real' food identical to mummy's food. Does he ever look at your plate? Does he ever ask for anything you are eating? It might help to ditch the spoon altogether. Again, looking for foods most kids are happy to eat, chips always seem to go down well, if he will eat a few chips you can begin to expand his self feeding diet by roasting sweet potato, turnip, butternut squash, carrots etc in a chip/baton/wedge form.
At 2yo I would imagine he isn't going to be too far of the 'I do it by myself' stage, it may be a few months off, but if you notice any 'do it myself' behaviour or phrases I would take advantage of that too.