meal time traumas

[shufflebum]

Ds is 18months, has always been a good eater but is becoming fussier and grumpier about mealtimes.
It often starts with trying to get him into his highchair which can be a 2 person job so sometimes I just let him sit on my lap which is marginally better but usually he still tantrums and arches his back till I let him down. He is refusing to eat anything at the table apart from blueberries (is totally obsessed with them!) I don't want meal times to turn into a battle and I don't want to use other food as bribery but am a bit stuck as to what to do.
He is teething and has a cold so I understand that he's not feeling great but he is happy to have snacks (cereal bars, fruit, biscuits)so is happy to eat on his terms. Frustratingly he never does this at nursery .
I try to parent in a "How to talk" type of way so any suggestions in this vein particularly appreciated!

My DS is a similar age, and atm will eat apricots and cheese (and he asks for them all the time.)

Even his beloved bananas have been dumped.

It is so frustrating.

He has just had a big ear infection, and was down to mainly milk, so maybe he'll improve over next 10 days or so?

He will eat biscuits to tbh.

Just noticed the end bit- yes! Mine will eat everything at nursery

Good to know I'm not alone! For breakfast I sat him on a normal chair on a cushion and spoon fed him some ready brek with his beloved blueberries in it. Managed to get about 5 spoonfuls in before he erupted into hysteria.
I haven't tried a floor picnic (sounds fun!)because I don't want that to become the norm because knowing him I'll be posting on here in a week saying "Help, DS will only eat his food sitting on the floor!"
I want him to know that he has to sit at the table to eat as I don't let him walk around with food so just feel I'd be setting myself up for more tantrums further down the line.

Firstly cut out snacks as unless they're really hungry it's always going to be harder. Then I would definitely sit him on his high chair or maybe try a booster seat but definitely no laps and offer the food - either let him feed himself or spoon feed whichever seems to work to start off with and when he starts protesting take it away until he calms down then reoffer. Don't offer an alternative and if he keeps refusing then he gets down. End of meal & no more eating until the next meal.
My DS1 started really messing around at this sort of age and I tried all sort until finally I realised he wanted to feed himself & sit in a proper chair (albeit with booster) along with this very hardline approach and within about a week we were pretty much back to normality.
LCN

Great minds obviously LCN as he didn't get a snack this morning apart from a few blackberries on our dog walk!
He ate a small tin of spaghetti hoops and a yoghurt for lunch so more than he has for ages. He did this sitting on a cushion on a normal kitchen chair but was mainly spoon fed. Am just about to order a booster seat as the cushions were a little precarious! Hopefully within time he normal adventurous appetite will be back and I can stop panicking if there is no Heinz in the house!