OK if it was me, I would tweak the nap routine a bit
Instead of putting him to sleep at 8am can you keep him awake with activity time breakfast snack
then outside for a fresh air - into our garden if you have one, or round the block so you can get a morning coffee?
Back home - and if lucky he would fall asleep in buggy park the buggy in the hallway and get yourself food and feed up - do not do chores
Hopefully this first nap will end up being a more substantial one of 90 mins or so fingers crossed taking you until around 1.30/2pm
Then a good lunch of finger foods crackers cheese nibbles in his high chair - in front of cartoons if you need to -
I would then try and get him outside again for a short walk/go to the shops get ourself a treat magazine/cake/ then home again
Dinner for him around 5pm...chopped up banana and crackers at least if e refuses all other food at least you'll know he has at least banana and it's calming properties nutritionally
Bath around 6 let him splash out his energy so maybe he'll have less energy for crying hey?!!?
Changed, dried and cuddles milk bottle he will surely grab it after his bath d you leave it beside him as he should have an appetite for it after all the fresh air and stimulation during the day
quiet story wrapped in blanket 7pm or so - dummy next to him so he can pick it up if he wants
into cot, night night
Now, I know he'll prob scream blue murder but try this and see how
you go
If you keep a consistent predictable daily routine and bed routine he will know what to expect etc and MAY cry less for you
(I've tested the above with all 3 of my kids and it worked a treat but I had to keep it the SAME I'm not a routine person but I HAD to become one)