They do go through phases all the time, some last longer than others. It will get better if you keep trying, honestly. Few ideas I would try:
1st maybe try cooking with him homemade versions of what he likes. He will find it fun and there is good chance he might try it. Fish finger might be easier to copy, blend cod, mould in longish tubs, cover with flour, dip in egg and then breadcrumbs (blend krisprolls) and fry in vegetable oil.
If he reaches a point where he doesn't mind trying it may then add few peas, let him cut them with scissors (fun) to make them into smaller pieces then repeat the above.
Try to eat all together, the same food, dads might not like it but us mums can take it easier.
After that i would gently bribe him with little treat, stay calm. Tell him he can try it a bit and if he doesn't like it then spit it, let him play with the food, especially peas or carrots.
Another thing, if he doesn't mind mash, great! You can hide carrots, butternut squash, sweet red peppers there.
Stay calm and be strong! Things will get better
Good luck